<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>6. Built-in Exceptions — Python 2.7.5 documentation</title>
<link rel="stylesheet" href="../_static/default.css" type="text/css" />
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../',
VERSION: '2.7.5',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="../_static/jquery.js"></script>
<script type="text/javascript" src="../_static/underscore.js"></script>
<script type="text/javascript" src="../_static/doctools.js"></script>
<script type="text/javascript" src="../_static/sidebar.js"></script>
<link rel="search" type="application/opensearchdescription+xml"
title="Search within Python 2.7.5 documentation"
href="../_static/opensearch.xml"/>
<link rel="author" title="About these documents" href="../about.html" />
<link rel="copyright" title="Copyright" href="../copyright.html" />
<link rel="top" title="Python 2.7.5 documentation" href="../index.html" />
<link rel="up" title="The Python Standard Library" href="index.html" />
<link rel="next" title="7. String Services" href="strings.html" />
<link rel="prev" title="5. Built-in Types" href="stdtypes.html" />
<link rel="shortcut icon" type="image/png" href="../_static/py.png" />
<script type="text/javascript" src="../_static/copybutton.js"></script>
</head>
<body>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="strings.html" title="7. String Services"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="stdtypes.html" title="5. Built-in Types"
accesskey="P">previous</a> |</li>
<li><img src="../_static/py.png" alt=""
style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="http://www.python.org/">Python</a> »</li>
<li>
<a href="../index.html">Python 2.7.5 documentation</a> »
</li>
<li><a href="index.html" accesskey="U">The Python Standard Library</a> »</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body">
<div class="section" id="module-exceptions">
<span id="built-in-exceptions"></span><span id="bltin-exceptions"></span><h1>6. Built-in Exceptions<a class="headerlink" href="#module-exceptions" title="Permalink to this headline">¶</a></h1>
<p>Exceptions should be class objects. The exceptions are defined in the module
<a class="reference internal" href="#module-exceptions" title="exceptions: Standard exception classes."><tt class="xref py py-mod docutils literal"><span class="pre">exceptions</span></tt></a>. This module never needs to be imported explicitly: the
exceptions are provided in the built-in namespace as well as the
<a class="reference internal" href="#module-exceptions" title="exceptions: Standard exception classes."><tt class="xref py py-mod docutils literal"><span class="pre">exceptions</span></tt></a> module.</p>
<p id="index-0">For class exceptions, in a <a class="reference internal" href="../reference/compound_stmts.html#try"><tt class="xref std std-keyword docutils literal"><span class="pre">try</span></tt></a> statement with an <a class="reference internal" href="../reference/compound_stmts.html#except"><tt class="xref std std-keyword docutils literal"><span class="pre">except</span></tt></a>
clause that mentions a particular class, that clause also handles any exception
classes derived from that class (but not exception classes from which <em>it</em> is
derived). Two exception classes that are not related via subclassing are never
equivalent, even if they have the same name.</p>
<p id="index-1">The built-in exceptions listed below can be generated by the interpreter or
built-in functions. Except where mentioned, they have an “associated value”
indicating the detailed cause of the error. This may be a string or a tuple
containing several items of information (e.g., an error code and a string
explaining the code). The associated value is the second argument to the
<a class="reference internal" href="../reference/simple_stmts.html#raise"><tt class="xref std std-keyword docutils literal"><span class="pre">raise</span></tt></a> statement. If the exception class is derived from the standard
root class <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>, the associated value is present as the
exception instance’s <tt class="xref py py-attr docutils literal"><span class="pre">args</span></tt> attribute.</p>
<p>User code can raise built-in exceptions. This can be used to test an exception
handler or to report an error condition “just like” the situation in which the
interpreter raises the same exception; but beware that there is nothing to
prevent user code from raising an inappropriate error.</p>
<p>The built-in exception classes can be sub-classed to define new exceptions;
programmers are encouraged to at least derive new exceptions from the
<a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a> class and not <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>. More information on
defining exceptions is available in the Python Tutorial under
<a class="reference internal" href="../tutorial/errors.html#tut-userexceptions"><em>User-defined Exceptions</em></a>.</p>
<p>The following exceptions are only used as base classes for other exceptions.</p>
<dl class="exception">
<dt id="exceptions.BaseException">
<em class="property">exception </em><tt class="descname">BaseException</tt><a class="headerlink" href="#exceptions.BaseException" title="Permalink to this definition">¶</a></dt>
<dd><p>The base class for all built-in exceptions. It is not meant to be directly
inherited by user-defined classes (for that, use <a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a>). If
<a class="reference internal" href="functions.html#str" title="str"><tt class="xref py py-func docutils literal"><span class="pre">str()</span></tt></a> or <a class="reference internal" href="functions.html#unicode" title="unicode"><tt class="xref py py-func docutils literal"><span class="pre">unicode()</span></tt></a> is called on an instance of this class, the
representation of the argument(s) to the instance are returned, or the empty
string when there were no arguments.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.5.</span></p>
<dl class="attribute">
<dt id="exceptions.BaseException.args">
<tt class="descname">args</tt><a class="headerlink" href="#exceptions.BaseException.args" title="Permalink to this definition">¶</a></dt>
<dd><p>The tuple of arguments given to the exception constructor. Some built-in
exceptions (like <a class="reference internal" href="#exceptions.IOError" title="exceptions.IOError"><tt class="xref py py-exc docutils literal"><span class="pre">IOError</span></tt></a>) expect a certain number of arguments and
assign a special meaning to the elements of this tuple, while others are
usually called only with a single string giving an error message.</p>
</dd></dl>
</dd></dl>
<dl class="exception">
<dt id="exceptions.Exception">
<em class="property">exception </em><tt class="descname">Exception</tt><a class="headerlink" href="#exceptions.Exception" title="Permalink to this definition">¶</a></dt>
<dd><p>All built-in, non-system-exiting exceptions are derived from this class. All
user-defined exceptions should also be derived from this class.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>Changed to inherit from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.StandardError">
<em class="property">exception </em><tt class="descname">StandardError</tt><a class="headerlink" href="#exceptions.StandardError" title="Permalink to this definition">¶</a></dt>
<dd><p>The base class for all built-in exceptions except <a class="reference internal" href="#exceptions.StopIteration" title="exceptions.StopIteration"><tt class="xref py py-exc docutils literal"><span class="pre">StopIteration</span></tt></a>,
<a class="reference internal" href="#exceptions.GeneratorExit" title="exceptions.GeneratorExit"><tt class="xref py py-exc docutils literal"><span class="pre">GeneratorExit</span></tt></a>, <a class="reference internal" href="#exceptions.KeyboardInterrupt" title="exceptions.KeyboardInterrupt"><tt class="xref py py-exc docutils literal"><span class="pre">KeyboardInterrupt</span></tt></a> and <a class="reference internal" href="#exceptions.SystemExit" title="exceptions.SystemExit"><tt class="xref py py-exc docutils literal"><span class="pre">SystemExit</span></tt></a>.
<a class="reference internal" href="#exceptions.StandardError" title="exceptions.StandardError"><tt class="xref py py-exc docutils literal"><span class="pre">StandardError</span></tt></a> itself is derived from <a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ArithmeticError">
<em class="property">exception </em><tt class="descname">ArithmeticError</tt><a class="headerlink" href="#exceptions.ArithmeticError" title="Permalink to this definition">¶</a></dt>
<dd><p>The base class for those built-in exceptions that are raised for various
arithmetic errors: <a class="reference internal" href="#exceptions.OverflowError" title="exceptions.OverflowError"><tt class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></tt></a>, <a class="reference internal" href="#exceptions.ZeroDivisionError" title="exceptions.ZeroDivisionError"><tt class="xref py py-exc docutils literal"><span class="pre">ZeroDivisionError</span></tt></a>,
<a class="reference internal" href="#exceptions.FloatingPointError" title="exceptions.FloatingPointError"><tt class="xref py py-exc docutils literal"><span class="pre">FloatingPointError</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.BufferError">
<em class="property">exception </em><tt class="descname">BufferError</tt><a class="headerlink" href="#exceptions.BufferError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a <a class="reference internal" href="../c-api/buffer.html#bufferobjects"><em>buffer</em></a> related operation cannot be
performed.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.LookupError">
<em class="property">exception </em><tt class="descname">LookupError</tt><a class="headerlink" href="#exceptions.LookupError" title="Permalink to this definition">¶</a></dt>
<dd><p>The base class for the exceptions that are raised when a key or index used on
a mapping or sequence is invalid: <a class="reference internal" href="#exceptions.IndexError" title="exceptions.IndexError"><tt class="xref py py-exc docutils literal"><span class="pre">IndexError</span></tt></a>, <a class="reference internal" href="#exceptions.KeyError" title="exceptions.KeyError"><tt class="xref py py-exc docutils literal"><span class="pre">KeyError</span></tt></a>. This
can be raised directly by <a class="reference internal" href="codecs.html#codecs.lookup" title="codecs.lookup"><tt class="xref py py-func docutils literal"><span class="pre">codecs.lookup()</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.EnvironmentError">
<em class="property">exception </em><tt class="descname">EnvironmentError</tt><a class="headerlink" href="#exceptions.EnvironmentError" title="Permalink to this definition">¶</a></dt>
<dd><p>The base class for exceptions that can occur outside the Python system:
<a class="reference internal" href="#exceptions.IOError" title="exceptions.IOError"><tt class="xref py py-exc docutils literal"><span class="pre">IOError</span></tt></a>, <a class="reference internal" href="#exceptions.OSError" title="exceptions.OSError"><tt class="xref py py-exc docutils literal"><span class="pre">OSError</span></tt></a>. When exceptions of this type are created with a
2-tuple, the first item is available on the instance’s <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-attr docutils literal"><span class="pre">errno</span></tt></a> attribute
(it is assumed to be an error number), and the second item is available on the
<tt class="xref py py-attr docutils literal"><span class="pre">strerror</span></tt> attribute (it is usually the associated error message). The
tuple itself is also available on the <tt class="xref py py-attr docutils literal"><span class="pre">args</span></tt> attribute.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.5.2.</span></p>
<p>When an <a class="reference internal" href="#exceptions.EnvironmentError" title="exceptions.EnvironmentError"><tt class="xref py py-exc docutils literal"><span class="pre">EnvironmentError</span></tt></a> exception is instantiated with a 3-tuple, the
first two items are available as above, while the third item is available on the
<tt class="xref py py-attr docutils literal"><span class="pre">filename</span></tt> attribute. However, for backwards compatibility, the
<tt class="xref py py-attr docutils literal"><span class="pre">args</span></tt> attribute contains only a 2-tuple of the first two constructor
arguments.</p>
<p>The <tt class="xref py py-attr docutils literal"><span class="pre">filename</span></tt> attribute is <tt class="docutils literal"><span class="pre">None</span></tt> when this exception is created with
other than 3 arguments. The <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-attr docutils literal"><span class="pre">errno</span></tt></a> and <tt class="xref py py-attr docutils literal"><span class="pre">strerror</span></tt> attributes are
also <tt class="docutils literal"><span class="pre">None</span></tt> when the instance was created with other than 2 or 3 arguments.
In this last case, <tt class="xref py py-attr docutils literal"><span class="pre">args</span></tt> contains the verbatim constructor arguments as a
tuple.</p>
</dd></dl>
<p>The following exceptions are the exceptions that are actually raised.</p>
<dl class="exception">
<dt id="exceptions.AssertionError">
<em class="property">exception </em><tt class="descname">AssertionError</tt><a class="headerlink" href="#exceptions.AssertionError" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-2">Raised when an <a class="reference internal" href="../reference/simple_stmts.html#assert"><tt class="xref std std-keyword docutils literal"><span class="pre">assert</span></tt></a> statement fails.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.AttributeError">
<em class="property">exception </em><tt class="descname">AttributeError</tt><a class="headerlink" href="#exceptions.AttributeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an attribute reference (see <a class="reference internal" href="../reference/expressions.html#attribute-references"><em>Attribute references</em></a>) or
assignment fails. (When an object does not support attribute references or
attribute assignments at all, <a class="reference internal" href="#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> is raised.)</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.EOFError">
<em class="property">exception </em><tt class="descname">EOFError</tt><a class="headerlink" href="#exceptions.EOFError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when one of the built-in functions (<a class="reference internal" href="functions.html#input" title="input"><tt class="xref py py-func docutils literal"><span class="pre">input()</span></tt></a> or <a class="reference internal" href="functions.html#raw_input" title="raw_input"><tt class="xref py py-func docutils literal"><span class="pre">raw_input()</span></tt></a>)
hits an end-of-file condition (EOF) without reading any data. (N.B.: the
<a class="reference internal" href="stdtypes.html#file.read" title="file.read"><tt class="xref py py-meth docutils literal"><span class="pre">file.read()</span></tt></a> and <a class="reference internal" href="stdtypes.html#file.readline" title="file.readline"><tt class="xref py py-meth docutils literal"><span class="pre">file.readline()</span></tt></a> methods return an empty string
when they hit EOF.)</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.FloatingPointError">
<em class="property">exception </em><tt class="descname">FloatingPointError</tt><a class="headerlink" href="#exceptions.FloatingPointError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a floating point operation fails. This exception is always defined,
but can only be raised when Python is configured with the
<tt class="docutils literal"><span class="pre">--with-fpectl</span></tt> option, or the <tt class="xref py py-const docutils literal"><span class="pre">WANT_SIGFPE_HANDLER</span></tt> symbol is
defined in the <tt class="file docutils literal"><span class="pre">pyconfig.h</span></tt> file.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.GeneratorExit">
<em class="property">exception </em><tt class="descname">GeneratorExit</tt><a class="headerlink" href="#exceptions.GeneratorExit" title="Permalink to this definition">¶</a></dt>
<dd><p>Raise when a <a class="reference internal" href="../glossary.html#term-generator"><em class="xref std std-term">generator</em></a>‘s <tt class="xref py py-meth docutils literal"><span class="pre">close()</span></tt> method is called. It
directly inherits from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a> instead of <a class="reference internal" href="#exceptions.StandardError" title="exceptions.StandardError"><tt class="xref py py-exc docutils literal"><span class="pre">StandardError</span></tt></a> since
it is technically not an error.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.5.</span></p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span>Changed to inherit from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.IOError">
<em class="property">exception </em><tt class="descname">IOError</tt><a class="headerlink" href="#exceptions.IOError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an I/O operation (such as a <a class="reference internal" href="../reference/simple_stmts.html#print"><tt class="xref std std-keyword docutils literal"><span class="pre">print</span></tt></a> statement, the built-in
<a class="reference internal" href="functions.html#open" title="open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a> function or a method of a file object) fails for an I/O-related
reason, e.g., “file not found” or “disk full”.</p>
<p>This class is derived from <a class="reference internal" href="#exceptions.EnvironmentError" title="exceptions.EnvironmentError"><tt class="xref py py-exc docutils literal"><span class="pre">EnvironmentError</span></tt></a>. See the discussion above
for more information on exception instance attributes.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span>Changed <a class="reference internal" href="socket.html#socket.error" title="socket.error"><tt class="xref py py-exc docutils literal"><span class="pre">socket.error</span></tt></a> to use this as a base class.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ImportError">
<em class="property">exception </em><tt class="descname">ImportError</tt><a class="headerlink" href="#exceptions.ImportError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an <a class="reference internal" href="../reference/simple_stmts.html#import"><tt class="xref std std-keyword docutils literal"><span class="pre">import</span></tt></a> statement fails to find the module definition
or when a <tt class="docutils literal"><span class="pre">from</span> <span class="pre">...</span> <span class="pre">import</span></tt> fails to find a name that is to be imported.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.IndexError">
<em class="property">exception </em><tt class="descname">IndexError</tt><a class="headerlink" href="#exceptions.IndexError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a sequence subscript is out of range. (Slice indices are silently
truncated to fall in the allowed range; if an index is not a plain integer,
<a class="reference internal" href="#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> is raised.)</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.KeyError">
<em class="property">exception </em><tt class="descname">KeyError</tt><a class="headerlink" href="#exceptions.KeyError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a mapping (dictionary) key is not found in the set of existing keys.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.KeyboardInterrupt">
<em class="property">exception </em><tt class="descname">KeyboardInterrupt</tt><a class="headerlink" href="#exceptions.KeyboardInterrupt" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when the user hits the interrupt key (normally <tt class="kbd docutils literal"><span class="pre">Control-C</span></tt> or
<tt class="kbd docutils literal"><span class="pre">Delete</span></tt>). During execution, a check for interrupts is made regularly.
Interrupts typed when a built-in function <a class="reference internal" href="functions.html#input" title="input"><tt class="xref py py-func docutils literal"><span class="pre">input()</span></tt></a> or <a class="reference internal" href="functions.html#raw_input" title="raw_input"><tt class="xref py py-func docutils literal"><span class="pre">raw_input()</span></tt></a> is
waiting for input also raise this exception. The exception inherits from
<a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a> so as to not be accidentally caught by code that catches
<a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a> and thus prevent the interpreter from exiting.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>Changed to inherit from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.MemoryError">
<em class="property">exception </em><tt class="descname">MemoryError</tt><a class="headerlink" href="#exceptions.MemoryError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an operation runs out of memory but the situation may still be
rescued (by deleting some objects). The associated value is a string indicating
what kind of (internal) operation ran out of memory. Note that because of the
underlying memory management architecture (C’s <tt class="xref c c-func docutils literal"><span class="pre">malloc()</span></tt> function), the
interpreter may not always be able to completely recover from this situation; it
nevertheless raises an exception so that a stack traceback can be printed, in
case a run-away program was the cause.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.NameError">
<em class="property">exception </em><tt class="descname">NameError</tt><a class="headerlink" href="#exceptions.NameError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a local or global name is not found. This applies only to
unqualified names. The associated value is an error message that includes the
name that could not be found.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.NotImplementedError">
<em class="property">exception </em><tt class="descname">NotImplementedError</tt><a class="headerlink" href="#exceptions.NotImplementedError" title="Permalink to this definition">¶</a></dt>
<dd><p>This exception is derived from <a class="reference internal" href="#exceptions.RuntimeError" title="exceptions.RuntimeError"><tt class="xref py py-exc docutils literal"><span class="pre">RuntimeError</span></tt></a>. In user defined base
classes, abstract methods should raise this exception when they require derived
classes to override the method.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.5.2.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.OSError">
<em class="property">exception </em><tt class="descname">OSError</tt><a class="headerlink" href="#exceptions.OSError" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-3">This exception is derived from <a class="reference internal" href="#exceptions.EnvironmentError" title="exceptions.EnvironmentError"><tt class="xref py py-exc docutils literal"><span class="pre">EnvironmentError</span></tt></a>. It is raised when a
function returns a system-related error (not for illegal argument types or
other incidental errors). The <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-attr docutils literal"><span class="pre">errno</span></tt></a> attribute is a numeric error
code from <tt class="xref c c-data docutils literal"><span class="pre">errno</span></tt>, and the <tt class="xref py py-attr docutils literal"><span class="pre">strerror</span></tt> attribute is the
corresponding string, as would be printed by the C function <tt class="xref c c-func docutils literal"><span class="pre">perror()</span></tt>.
See the module <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-mod docutils literal"><span class="pre">errno</span></tt></a>, which contains names for the error codes defined
by the underlying operating system.</p>
<p>For exceptions that involve a file system path (such as <tt class="xref py py-func docutils literal"><span class="pre">chdir()</span></tt> or
<tt class="xref py py-func docutils literal"><span class="pre">unlink()</span></tt>), the exception instance will contain a third attribute,
<tt class="xref py py-attr docutils literal"><span class="pre">filename</span></tt>, which is the file name passed to the function.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.5.2.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.OverflowError">
<em class="property">exception </em><tt class="descname">OverflowError</tt><a class="headerlink" href="#exceptions.OverflowError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when the result of an arithmetic operation is too large to be
represented. This cannot occur for long integers (which would rather raise
<a class="reference internal" href="#exceptions.MemoryError" title="exceptions.MemoryError"><tt class="xref py py-exc docutils literal"><span class="pre">MemoryError</span></tt></a> than give up) and for most operations with plain integers,
which return a long integer instead. Because of the lack of standardization
of floating point exception handling in C, most floating point operations
also aren’t checked.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ReferenceError">
<em class="property">exception </em><tt class="descname">ReferenceError</tt><a class="headerlink" href="#exceptions.ReferenceError" title="Permalink to this definition">¶</a></dt>
<dd><p>This exception is raised when a weak reference proxy, created by the
<a class="reference internal" href="weakref.html#weakref.proxy" title="weakref.proxy"><tt class="xref py py-func docutils literal"><span class="pre">weakref.proxy()</span></tt></a> function, is used to access an attribute of the referent
after it has been garbage collected. For more information on weak references,
see the <a class="reference internal" href="weakref.html#module-weakref" title="weakref: Support for weak references and weak dictionaries."><tt class="xref py py-mod docutils literal"><span class="pre">weakref</span></tt></a> module.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.2: </span>Previously known as the <a class="reference internal" href="weakref.html#weakref.ReferenceError" title="weakref.ReferenceError"><tt class="xref py py-exc docutils literal"><span class="pre">weakref.ReferenceError</span></tt></a> exception.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.RuntimeError">
<em class="property">exception </em><tt class="descname">RuntimeError</tt><a class="headerlink" href="#exceptions.RuntimeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an error is detected that doesn’t fall in any of the other
categories. The associated value is a string indicating what precisely went
wrong. (This exception is mostly a relic from a previous version of the
interpreter; it is not used very much any more.)</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.StopIteration">
<em class="property">exception </em><tt class="descname">StopIteration</tt><a class="headerlink" href="#exceptions.StopIteration" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised by an <a class="reference internal" href="../glossary.html#term-iterator"><em class="xref std std-term">iterator</em></a>‘s <a class="reference internal" href="stdtypes.html#iterator.next" title="iterator.next"><tt class="xref py py-meth docutils literal"><span class="pre">next()</span></tt></a> method to signal that
there are no further values. This is derived from <a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a> rather
than <a class="reference internal" href="#exceptions.StandardError" title="exceptions.StandardError"><tt class="xref py py-exc docutils literal"><span class="pre">StandardError</span></tt></a>, since this is not considered an error in its
normal application.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.2.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.SyntaxError">
<em class="property">exception </em><tt class="descname">SyntaxError</tt><a class="headerlink" href="#exceptions.SyntaxError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when the parser encounters a syntax error. This may occur in an
<a class="reference internal" href="../reference/simple_stmts.html#import"><tt class="xref std std-keyword docutils literal"><span class="pre">import</span></tt></a> statement, in an <a class="reference internal" href="../reference/simple_stmts.html#exec"><tt class="xref std std-keyword docutils literal"><span class="pre">exec</span></tt></a> statement, in a call to the
built-in function <a class="reference internal" href="functions.html#eval" title="eval"><tt class="xref py py-func docutils literal"><span class="pre">eval()</span></tt></a> or <a class="reference internal" href="functions.html#input" title="input"><tt class="xref py py-func docutils literal"><span class="pre">input()</span></tt></a>, or when reading the initial
script or standard input (also interactively).</p>
<p>Instances of this class have attributes <tt class="xref py py-attr docutils literal"><span class="pre">filename</span></tt>, <tt class="xref py py-attr docutils literal"><span class="pre">lineno</span></tt>,
<tt class="xref py py-attr docutils literal"><span class="pre">offset</span></tt> and <tt class="xref py py-attr docutils literal"><span class="pre">text</span></tt> for easier access to the details. <a class="reference internal" href="functions.html#str" title="str"><tt class="xref py py-func docutils literal"><span class="pre">str()</span></tt></a>
of the exception instance returns only the message.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.IndentationError">
<em class="property">exception </em><tt class="descname">IndentationError</tt><a class="headerlink" href="#exceptions.IndentationError" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for syntax errors related to incorrect indentation. This is a
subclass of <a class="reference internal" href="#exceptions.SyntaxError" title="exceptions.SyntaxError"><tt class="xref py py-exc docutils literal"><span class="pre">SyntaxError</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.TabError">
<em class="property">exception </em><tt class="descname">TabError</tt><a class="headerlink" href="#exceptions.TabError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when indentation contains an inconsistent use of tabs and spaces.
This is a subclass of <a class="reference internal" href="#exceptions.IndentationError" title="exceptions.IndentationError"><tt class="xref py py-exc docutils literal"><span class="pre">IndentationError</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.SystemError">
<em class="property">exception </em><tt class="descname">SystemError</tt><a class="headerlink" href="#exceptions.SystemError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when the interpreter finds an internal error, but the situation does not
look so serious to cause it to abandon all hope. The associated value is a
string indicating what went wrong (in low-level terms).</p>
<p>You should report this to the author or maintainer of your Python interpreter.
Be sure to report the version of the Python interpreter (<tt class="docutils literal"><span class="pre">sys.version</span></tt>; it is
also printed at the start of an interactive Python session), the exact error
message (the exception’s associated value) and if possible the source of the
program that triggered the error.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.SystemExit">
<em class="property">exception </em><tt class="descname">SystemExit</tt><a class="headerlink" href="#exceptions.SystemExit" title="Permalink to this definition">¶</a></dt>
<dd><p>This exception is raised by the <a class="reference internal" href="sys.html#sys.exit" title="sys.exit"><tt class="xref py py-func docutils literal"><span class="pre">sys.exit()</span></tt></a> function. When it is not
handled, the Python interpreter exits; no stack traceback is printed. If the
associated value is a plain integer, it specifies the system exit status (passed
to C’s <tt class="xref c c-func docutils literal"><span class="pre">exit()</span></tt> function); if it is <tt class="docutils literal"><span class="pre">None</span></tt>, the exit status is zero; if
it has another type (such as a string), the object’s value is printed and the
exit status is one.</p>
<p>Instances have an attribute <a class="reference internal" href="code.html#module-code" title="code: Facilities to implement read-eval-print loops."><tt class="xref py py-attr docutils literal"><span class="pre">code</span></tt></a> which is set to the proposed exit
status or error message (defaulting to <tt class="docutils literal"><span class="pre">None</span></tt>). Also, this exception derives
directly from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a> and not <a class="reference internal" href="#exceptions.StandardError" title="exceptions.StandardError"><tt class="xref py py-exc docutils literal"><span class="pre">StandardError</span></tt></a>, since it is not
technically an error.</p>
<p>A call to <a class="reference internal" href="sys.html#sys.exit" title="sys.exit"><tt class="xref py py-func docutils literal"><span class="pre">sys.exit()</span></tt></a> is translated into an exception so that clean-up
handlers (<a class="reference internal" href="../reference/compound_stmts.html#finally"><tt class="xref std std-keyword docutils literal"><span class="pre">finally</span></tt></a> clauses of <a class="reference internal" href="../reference/compound_stmts.html#try"><tt class="xref std std-keyword docutils literal"><span class="pre">try</span></tt></a> statements) can be
executed, and so that a debugger can execute a script without running the risk
of losing control. The <a class="reference internal" href="os.html#os._exit" title="os._exit"><tt class="xref py py-func docutils literal"><span class="pre">os._exit()</span></tt></a> function can be used if it is
absolutely positively necessary to exit immediately (for example, in the child
process after a call to <tt class="xref py py-func docutils literal"><span class="pre">fork()</span></tt>).</p>
<p>The exception inherits from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a> instead of <a class="reference internal" href="#exceptions.StandardError" title="exceptions.StandardError"><tt class="xref py py-exc docutils literal"><span class="pre">StandardError</span></tt></a>
or <a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a> so that it is not accidentally caught by code that catches
<a class="reference internal" href="#exceptions.Exception" title="exceptions.Exception"><tt class="xref py py-exc docutils literal"><span class="pre">Exception</span></tt></a>. This allows the exception to properly propagate up and cause
the interpreter to exit.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>Changed to inherit from <a class="reference internal" href="#exceptions.BaseException" title="exceptions.BaseException"><tt class="xref py py-exc docutils literal"><span class="pre">BaseException</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.TypeError">
<em class="property">exception </em><tt class="descname">TypeError</tt><a class="headerlink" href="#exceptions.TypeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when an operation or function is applied to an object of inappropriate
type. The associated value is a string giving details about the type mismatch.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnboundLocalError">
<em class="property">exception </em><tt class="descname">UnboundLocalError</tt><a class="headerlink" href="#exceptions.UnboundLocalError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a reference is made to a local variable in a function or method, but
no value has been bound to that variable. This is a subclass of
<a class="reference internal" href="#exceptions.NameError" title="exceptions.NameError"><tt class="xref py py-exc docutils literal"><span class="pre">NameError</span></tt></a>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.0.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnicodeError">
<em class="property">exception </em><tt class="descname">UnicodeError</tt><a class="headerlink" href="#exceptions.UnicodeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a Unicode-related encoding or decoding error occurs. It is a
subclass of <a class="reference internal" href="#exceptions.ValueError" title="exceptions.ValueError"><tt class="xref py py-exc docutils literal"><span class="pre">ValueError</span></tt></a>.</p>
<p><a class="reference internal" href="#exceptions.UnicodeError" title="exceptions.UnicodeError"><tt class="xref py py-exc docutils literal"><span class="pre">UnicodeError</span></tt></a> has attributes that describe the encoding or decoding
error. For example, <tt class="docutils literal"><span class="pre">err.object[err.start:err.end]</span></tt> gives the particular
invalid input that the codec failed on.</p>
<dl class="attribute">
<dt id="exceptions.UnicodeError.encoding">
<tt class="descname">encoding</tt><a class="headerlink" href="#exceptions.UnicodeError.encoding" title="Permalink to this definition">¶</a></dt>
<dd><p>The name of the encoding that raised the error.</p>
</dd></dl>
<dl class="attribute">
<dt id="exceptions.UnicodeError.reason">
<tt class="descname">reason</tt><a class="headerlink" href="#exceptions.UnicodeError.reason" title="Permalink to this definition">¶</a></dt>
<dd><p>A string describing the specific codec error.</p>
</dd></dl>
<dl class="attribute">
<dt id="exceptions.UnicodeError.object">
<tt class="descname">object</tt><a class="headerlink" href="#exceptions.UnicodeError.object" title="Permalink to this definition">¶</a></dt>
<dd><p>The object the codec was attempting to encode or decode.</p>
</dd></dl>
<dl class="attribute">
<dt id="exceptions.UnicodeError.start">
<tt class="descname">start</tt><a class="headerlink" href="#exceptions.UnicodeError.start" title="Permalink to this definition">¶</a></dt>
<dd><p>The first index of invalid data in <a class="reference internal" href="functions.html#object" title="object"><tt class="xref py py-attr docutils literal"><span class="pre">object</span></tt></a>.</p>
</dd></dl>
<dl class="attribute">
<dt id="exceptions.UnicodeError.end">
<tt class="descname">end</tt><a class="headerlink" href="#exceptions.UnicodeError.end" title="Permalink to this definition">¶</a></dt>
<dd><p>The index after the last invalid data in <a class="reference internal" href="functions.html#object" title="object"><tt class="xref py py-attr docutils literal"><span class="pre">object</span></tt></a>.</p>
</dd></dl>
<p class="versionadded">
<span class="versionmodified">New in version 2.0.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnicodeEncodeError">
<em class="property">exception </em><tt class="descname">UnicodeEncodeError</tt><a class="headerlink" href="#exceptions.UnicodeEncodeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a Unicode-related error occurs during encoding. It is a subclass of
<a class="reference internal" href="#exceptions.UnicodeError" title="exceptions.UnicodeError"><tt class="xref py py-exc docutils literal"><span class="pre">UnicodeError</span></tt></a>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnicodeDecodeError">
<em class="property">exception </em><tt class="descname">UnicodeDecodeError</tt><a class="headerlink" href="#exceptions.UnicodeDecodeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a Unicode-related error occurs during decoding. It is a subclass of
<a class="reference internal" href="#exceptions.UnicodeError" title="exceptions.UnicodeError"><tt class="xref py py-exc docutils literal"><span class="pre">UnicodeError</span></tt></a>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnicodeTranslateError">
<em class="property">exception </em><tt class="descname">UnicodeTranslateError</tt><a class="headerlink" href="#exceptions.UnicodeTranslateError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a Unicode-related error occurs during translating. It is a subclass
of <a class="reference internal" href="#exceptions.UnicodeError" title="exceptions.UnicodeError"><tt class="xref py py-exc docutils literal"><span class="pre">UnicodeError</span></tt></a>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ValueError">
<em class="property">exception </em><tt class="descname">ValueError</tt><a class="headerlink" href="#exceptions.ValueError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a built-in operation or function receives an argument that has the
right type but an inappropriate value, and the situation is not described by a
more precise exception such as <a class="reference internal" href="#exceptions.IndexError" title="exceptions.IndexError"><tt class="xref py py-exc docutils literal"><span class="pre">IndexError</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.VMSError">
<em class="property">exception </em><tt class="descname">VMSError</tt><a class="headerlink" href="#exceptions.VMSError" title="Permalink to this definition">¶</a></dt>
<dd><p>Only available on VMS. Raised when a VMS-specific error occurs.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.WindowsError">
<em class="property">exception </em><tt class="descname">WindowsError</tt><a class="headerlink" href="#exceptions.WindowsError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when a Windows-specific error occurs or when the error number does not
correspond to an <tt class="xref c c-data docutils literal"><span class="pre">errno</span></tt> value. The <tt class="xref py py-attr docutils literal"><span class="pre">winerror</span></tt> and
<tt class="xref py py-attr docutils literal"><span class="pre">strerror</span></tt> values are created from the return values of the
<tt class="xref c c-func docutils literal"><span class="pre">GetLastError()</span></tt> and <tt class="xref c c-func docutils literal"><span class="pre">FormatMessage()</span></tt> functions from the Windows
Platform API. The <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-attr docutils literal"><span class="pre">errno</span></tt></a> value maps the <tt class="xref py py-attr docutils literal"><span class="pre">winerror</span></tt> value to
corresponding <tt class="docutils literal"><span class="pre">errno.h</span></tt> values. This is a subclass of <a class="reference internal" href="#exceptions.OSError" title="exceptions.OSError"><tt class="xref py py-exc docutils literal"><span class="pre">OSError</span></tt></a>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.0.</span></p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>Previous versions put the <tt class="xref c c-func docutils literal"><span class="pre">GetLastError()</span></tt> codes into <a class="reference internal" href="errno.html#module-errno" title="errno: Standard errno system symbols."><tt class="xref py py-attr docutils literal"><span class="pre">errno</span></tt></a>.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ZeroDivisionError">
<em class="property">exception </em><tt class="descname">ZeroDivisionError</tt><a class="headerlink" href="#exceptions.ZeroDivisionError" title="Permalink to this definition">¶</a></dt>
<dd><p>Raised when the second argument of a division or modulo operation is zero. The
associated value is a string indicating the type of the operands and the
operation.</p>
</dd></dl>
<p>The following exceptions are used as warning categories; see the <a class="reference internal" href="warnings.html#module-warnings" title="warnings: Issue warning messages and control their disposition."><tt class="xref py py-mod docutils literal"><span class="pre">warnings</span></tt></a>
module for more information.</p>
<dl class="exception">
<dt id="exceptions.Warning">
<em class="property">exception </em><tt class="descname">Warning</tt><a class="headerlink" href="#exceptions.Warning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warning categories.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UserWarning">
<em class="property">exception </em><tt class="descname">UserWarning</tt><a class="headerlink" href="#exceptions.UserWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings generated by user code.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.DeprecationWarning">
<em class="property">exception </em><tt class="descname">DeprecationWarning</tt><a class="headerlink" href="#exceptions.DeprecationWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about deprecated features.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.PendingDeprecationWarning">
<em class="property">exception </em><tt class="descname">PendingDeprecationWarning</tt><a class="headerlink" href="#exceptions.PendingDeprecationWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about features which will be deprecated in the future.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.SyntaxWarning">
<em class="property">exception </em><tt class="descname">SyntaxWarning</tt><a class="headerlink" href="#exceptions.SyntaxWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about dubious syntax</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.RuntimeWarning">
<em class="property">exception </em><tt class="descname">RuntimeWarning</tt><a class="headerlink" href="#exceptions.RuntimeWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about dubious runtime behavior.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.FutureWarning">
<em class="property">exception </em><tt class="descname">FutureWarning</tt><a class="headerlink" href="#exceptions.FutureWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about constructs that will change semantically in the
future.</p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.ImportWarning">
<em class="property">exception </em><tt class="descname">ImportWarning</tt><a class="headerlink" href="#exceptions.ImportWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings about probable mistakes in module imports.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.5.</span></p>
</dd></dl>
<dl class="exception">
<dt id="exceptions.UnicodeWarning">
<em class="property">exception </em><tt class="descname">UnicodeWarning</tt><a class="headerlink" href="#exceptions.UnicodeWarning" title="Permalink to this definition">¶</a></dt>
<dd><p>Base class for warnings related to Unicode.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.5.</span></p>
</dd></dl>
<div class="section" id="exception-hierarchy">
<h2>6.1. Exception hierarchy<a class="headerlink" href="#exception-hierarchy" title="Permalink to this headline">¶</a></h2>
<p>The class hierarchy for built-in exceptions is:</p>
<div class="highlight-python"><pre>BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- StopIteration
+-- StandardError
| +-- BufferError
| +-- ArithmeticError
| | +-- FloatingPointError
| | +-- OverflowError
| | +-- ZeroDivisionError
| +-- AssertionError
| +-- AttributeError
| +-- EnvironmentError
| | +-- IOError
| | +-- OSError
| | +-- WindowsError (Windows)
| | +-- VMSError (VMS)
| +-- EOFError
| +-- ImportError
| +-- LookupError
| | +-- IndexError
| | +-- KeyError
| +-- MemoryError
| +-- NameError
| | +-- UnboundLocalError
| +-- ReferenceError
| +-- RuntimeError
| | +-- NotImplementedError
| +-- SyntaxError
| | +-- IndentationError
| | +-- TabError
| +-- SystemError
| +-- TypeError
| +-- ValueError
| +-- UnicodeError
| +-- UnicodeDecodeError
| +-- UnicodeEncodeError
| +-- UnicodeTranslateError
+-- Warning
+-- DeprecationWarning
+-- PendingDeprecationWarning
+-- RuntimeWarning
+-- SyntaxWarning
+-- UserWarning
+-- FutureWarning
+-- ImportWarning
+-- UnicodeWarning
+-- BytesWarning
</pre>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<h3><a href="../contents.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">6. Built-in Exceptions</a><ul>
<li><a class="reference internal" href="#exception-hierarchy">6.1. Exception hierarchy</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="stdtypes.html"
title="previous chapter">5. Built-in Types</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="strings.html"
title="next chapter">7. String Services</a></p>
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">Report a Bug</a></li>
<li><a href="../_sources/library/exceptions.txt"
rel="nofollow">Show Source</a></li>
</ul>
<div id="searchbox" style="display: none">
<h3>Quick search</h3>
<form class="search" action="../search.html" method="get">
<input type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p class="searchtip" style="font-size: 90%">
Enter search terms or a module, class or function name.
</p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="strings.html" title="7. String Services"
>next</a> |</li>
<li class="right" >
<a href="stdtypes.html" title="5. Built-in Types"
>previous</a> |</li>
<li><img src="../_static/py.png" alt=""
style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="http://www.python.org/">Python</a> »</li>
<li>
<a href="../index.html">Python 2.7.5 documentation</a> »
</li>
<li><a href="index.html" >The Python Standard Library</a> »</li>
</ul>
</div>
<div class="footer">
© <a href="../copyright.html">Copyright</a> 1990-2019, Python Software Foundation.
<br />
The Python Software Foundation is a non-profit corporation.
<a href="http://www.python.org/psf/donations/">Please donate.</a>
<br />
Last updated on Jul 03, 2019.
<a href="../bugs.html">Found a bug</a>?
<br />
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3.
</div>
</body>
</html>| Name | Type | Size | Permission | Actions |
|---|---|---|---|---|
| 2to3.html | File | 49.27 KB | 0644 |
|
| __builtin__.html | File | 10.26 KB | 0644 |
|
| __future__.html | File | 13.79 KB | 0644 |
|
| __main__.html | File | 7.05 KB | 0644 |
|
| _winreg.html | File | 59.21 KB | 0644 |
|
| abc.html | File | 23.9 KB | 0644 |
|
| aepack.html | File | 13.16 KB | 0644 |
|
| aetools.html | File | 14.91 KB | 0644 |
|
| aetypes.html | File | 18.88 KB | 0644 |
|
| aifc.html | File | 22.4 KB | 0644 |
|
| al.html | File | 17.34 KB | 0644 |
|
| allos.html | File | 33.72 KB | 0644 |
|
| anydbm.html | File | 16.33 KB | 0644 |
|
| archiving.html | File | 9.26 KB | 0644 |
|
| argparse.html | File | 237.62 KB | 0644 |
|
| array.html | File | 29.29 KB | 0644 |
|
| ast.html | File | 34.98 KB | 0644 |
|
| asynchat.html | File | 31.43 KB | 0644 |
|
| asyncore.html | File | 36.51 KB | 0644 |
|
| atexit.html | File | 16.8 KB | 0644 |
|
| audioop.html | File | 31.36 KB | 0644 |
|
| autogil.html | File | 8.19 KB | 0644 |
|
| base64.html | File | 19.67 KB | 0644 |
|
| basehttpserver.html | File | 34.04 KB | 0644 |
|
| bastion.html | File | 11.04 KB | 0644 |
|
| bdb.html | File | 36.68 KB | 0644 |
|
| binascii.html | File | 20.67 KB | 0644 |
|
| binhex.html | File | 10.58 KB | 0644 |
|
| bisect.html | File | 23.24 KB | 0644 |
|
| bsddb.html | File | 26.43 KB | 0644 |
|
| bz2.html | File | 26.08 KB | 0644 |
|
| calendar.html | File | 37.79 KB | 0644 |
|
| carbon.html | File | 48.94 KB | 0644 |
|
| cd.html | File | 27.96 KB | 0644 |
|
| cgi.html | File | 49.92 KB | 0644 |
|
| cgihttpserver.html | File | 13.1 KB | 0644 |
|
| cgitb.html | File | 11.41 KB | 0644 |
|
| chunk.html | File | 14.66 KB | 0644 |
|
| cmath.html | File | 25.63 KB | 0644 |
|
| cmd.html | File | 26.09 KB | 0644 |
|
| code.html | File | 24.58 KB | 0644 |
|
| codecs.html | File | 100.64 KB | 0644 |
|
| codeop.html | File | 14.84 KB | 0644 |
|
| collections.html | File | 133.96 KB | 0644 |
|
| colorpicker.html | File | 7.52 KB | 0644 |
|
| colorsys.html | File | 11.04 KB | 0644 |
|
| commands.html | File | 14.36 KB | 0644 |
|
| compileall.html | File | 16.83 KB | 0644 |
|
| compiler.html | File | 67.75 KB | 0644 |
|
| configparser.html | File | 62.13 KB | 0644 |
|
| constants.html | File | 12.83 KB | 0644 |
|
| contextlib.html | File | 19.39 KB | 0644 |
|
| cookie.html | File | 39.07 KB | 0644 |
|
| cookielib.html | File | 83.82 KB | 0644 |
|
| copy.html | File | 12.19 KB | 0644 |
|
| copy_reg.html | File | 13.76 KB | 0644 |
|
| crypt.html | File | 10.04 KB | 0644 |
|
| crypto.html | File | 7.59 KB | 0644 |
|
| csv.html | File | 67.37 KB | 0644 |
|
| ctypes.html | File | 238.78 KB | 0644 |
|
| curses.ascii.html | File | 22.29 KB | 0644 |
|
| curses.html | File | 146.63 KB | 0644 |
|
| curses.panel.html | File | 14.39 KB | 0644 |
|
| custominterp.html | File | 7.62 KB | 0644 |
|
| datatypes.html | File | 16.84 KB | 0644 |
|
| datetime.html | File | 226.59 KB | 0644 |
|
| dbhash.html | File | 15.48 KB | 0644 |
|
| dbm.html | File | 12.07 KB | 0644 |
|
| debug.html | File | 10.15 KB | 0644 |
|
| decimal.html | File | 194.44 KB | 0644 |
|
| development.html | File | 14.17 KB | 0644 |
|
| difflib.html | File | 84.83 KB | 0644 |
|
| dircache.html | File | 11.41 KB | 0644 |
|
| dis.html | File | 69.95 KB | 0644 |
|
| distutils.html | File | 8.05 KB | 0644 |
|
| dl.html | File | 16.33 KB | 0644 |
|
| doctest.html | File | 165.54 KB | 0644 |
|
| docxmlrpcserver.html | File | 16.43 KB | 0644 |
|
| dumbdbm.html | File | 14.02 KB | 0644 |
|
| dummy_thread.html | File | 9.43 KB | 0644 |
|
| dummy_threading.html | File | 8.37 KB | 0644 |
|
| easydialogs.html | File | 30.55 KB | 0644 |
|
| email-examples.html | File | 45.65 KB | 0644 |
|
| email.charset.html | File | 26.8 KB | 0644 |
|
| email.encoders.html | File | 11.86 KB | 0644 |
|
| email.errors.html | File | 15.77 KB | 0644 |
|
| email.generator.html | File | 20.77 KB | 0644 |
|
| email.header.html | File | 26.92 KB | 0644 |
|
| email.html | File | 44.24 KB | 0644 |
|
| email.iterators.html | File | 11.52 KB | 0644 |
|
| email.message.html | File | 63.16 KB | 0644 |
|
| email.mime.html | File | 27.93 KB | 0644 |
|
| email.parser.html | File | 30.45 KB | 0644 |
|
| email.util.html | File | 24.46 KB | 0644 |
|
| errno.html | File | 37.99 KB | 0644 |
|
| exceptions.html | File | 56.13 KB | 0644 |
|
| fcntl.html | File | 22.67 KB | 0644 |
|
| filecmp.html | File | 22.3 KB | 0644 |
|
| fileformats.html | File | 9.14 KB | 0644 |
|
| fileinput.html | File | 24.28 KB | 0644 |
|
| filesys.html | File | 10.2 KB | 0644 |
|
| fl.html | File | 49.92 KB | 0644 |
|
| fm.html | File | 11.91 KB | 0644 |
|
| fnmatch.html | File | 14.58 KB | 0644 |
|
| formatter.html | File | 34.06 KB | 0644 |
|
| fpectl.html | File | 16.01 KB | 0644 |
|
| fpformat.html | File | 10.59 KB | 0644 |
|
| fractions.html | File | 22.61 KB | 0644 |
|
| framework.html | File | 33.34 KB | 0644 |
|
| frameworks.html | File | 7.14 KB | 0644 |
|
| ftplib.html | File | 43.99 KB | 0644 |
|
| functions.html | File | 183.14 KB | 0644 |
|
| functools.html | File | 27.17 KB | 0644 |
|
| future_builtins.html | File | 13.04 KB | 0644 |
|
| gc.html | File | 25.75 KB | 0644 |
|
| gdbm.html | File | 15.96 KB | 0644 |
|
| gensuitemodule.html | File | 11.51 KB | 0644 |
|
| getopt.html | File | 23.66 KB | 0644 |
|
| getpass.html | File | 10.65 KB | 0644 |
|
| gettext.html | File | 78.76 KB | 0644 |
|
| gl.html | File | 22.09 KB | 0644 |
|
| glob.html | File | 13.26 KB | 0644 |
|
| grp.html | File | 10.49 KB | 0644 |
|
| gzip.html | File | 18.99 KB | 0644 |
|
| hashlib.html | File | 18.2 KB | 0644 |
|
| heapq.html | File | 31.61 KB | 0644 |
|
| hmac.html | File | 10.46 KB | 0644 |
|
| hotshot.html | File | 18.65 KB | 0644 |
|
| htmllib.html | File | 25.32 KB | 0644 |
|
| htmlparser.html | File | 39.11 KB | 0644 |
|
| httplib.html | File | 62.95 KB | 0644 |
|
| i18n.html | File | 9.52 KB | 0644 |
|
| ic.html | File | 17.17 KB | 0644 |
|
| idle.html | File | 20.9 KB | 0644 |
|
| imageop.html | File | 14.76 KB | 0644 |
|
| imaplib.html | File | 51.99 KB | 0644 |
|
| imgfile.html | File | 11.71 KB | 0644 |
|
| imghdr.html | File | 11.3 KB | 0644 |
|
| imp.html | File | 34.34 KB | 0644 |
|
| importlib.html | File | 8.26 KB | 0644 |
|
| imputil.html | File | 31.81 KB | 0644 |
|
| index.html | File | 72.78 KB | 0644 |
|
| inspect.html | File | 50.71 KB | 0644 |
|
| internet.html | File | 24.87 KB | 0644 |
|
| intro.html | File | 8.93 KB | 0644 |
|
| io.html | File | 98.13 KB | 0644 |
|
| ipc.html | File | 13.41 KB | 0644 |
|
| itertools.html | File | 115.91 KB | 0644 |
|
| jpeg.html | File | 12.74 KB | 0644 |
|
| json.html | File | 67.04 KB | 0644 |
|
| keyword.html | File | 7.68 KB | 0644 |
|
| language.html | File | 11.03 KB | 0644 |
|
| linecache.html | File | 10.59 KB | 0644 |
|
| locale.html | File | 55.14 KB | 0644 |
|
| logging.config.html | File | 63.36 KB | 0644 |
|
| logging.handlers.html | File | 69.64 KB | 0644 |
|
| logging.html | File | 95.64 KB | 0644 |
|
| mac.html | File | 21.79 KB | 0644 |
|
| macos.html | File | 14.76 KB | 0644 |
|
| macosa.html | File | 12.96 KB | 0644 |
|
| macostools.html | File | 15.52 KB | 0644 |
|
| macpath.html | File | 7.76 KB | 0644 |
|
| mailbox.html | File | 156.75 KB | 0644 |
|
| mailcap.html | File | 13.21 KB | 0644 |
|
| markup.html | File | 18.77 KB | 0644 |
|
| marshal.html | File | 17.98 KB | 0644 |
|
| math.html | File | 39.24 KB | 0644 |
|
| md5.html | File | 13.97 KB | 0644 |
|
| mhlib.html | File | 21.54 KB | 0644 |
|
| mimetools.html | File | 19.25 KB | 0644 |
|
| mimetypes.html | File | 28.39 KB | 0644 |
|
| mimewriter.html | File | 15.02 KB | 0644 |
|
| mimify.html | File | 13.36 KB | 0644 |
|
| miniaeframe.html | File | 12.2 KB | 0644 |
|
| misc.html | File | 6.87 KB | 0644 |
|
| mm.html | File | 9.03 KB | 0644 |
|
| mmap.html | File | 28.36 KB | 0644 |
|
| modulefinder.html | File | 15.31 KB | 0644 |
|
| modules.html | File | 8.46 KB | 0644 |
|
| msilib.html | File | 52.43 KB | 0644 |
|
| msvcrt.html | File | 19.37 KB | 0644 |
|
| multifile.html | File | 24.3 KB | 0644 |
|
| multiprocessing.html | File | 365.71 KB | 0644 |
|
| mutex.html | File | 11.23 KB | 0644 |
|
| netdata.html | File | 16.98 KB | 0644 |
|
| netrc.html | File | 12.3 KB | 0644 |
|
| new.html | File | 12.12 KB | 0644 |
|
| nis.html | File | 10.64 KB | 0644 |
|
| nntplib.html | File | 41.92 KB | 0644 |
|
| numbers.html | File | 37.75 KB | 0644 |
|
| numeric.html | File | 13.55 KB | 0644 |
|
| operator.html | File | 82 KB | 0644 |
|
| optparse.html | File | 222.56 KB | 0644 |
|
| os.html | File | 214.25 KB | 0644 |
|
| os.path.html | File | 38.34 KB | 0644 |
|
| ossaudiodev.html | File | 41.5 KB | 0644 |
|
| othergui.html | File | 9.08 KB | 0644 |
|
| parser.html | File | 39.36 KB | 0644 |
|
| pdb.html | File | 33.96 KB | 0644 |
|
| persistence.html | File | 14.87 KB | 0644 |
|
| pickle.html | File | 102.27 KB | 0644 |
|
| pickletools.html | File | 10.63 KB | 0644 |
|
| pipes.html | File | 18.01 KB | 0644 |
|
| pkgutil.html | File | 25.11 KB | 0644 |
|
| platform.html | File | 28.37 KB | 0644 |
|
| plistlib.html | File | 17.03 KB | 0644 |
|
| popen2.html | File | 25.43 KB | 0644 |
|
| poplib.html | File | 22.32 KB | 0644 |
|
| posix.html | File | 14.41 KB | 0644 |
|
| posixfile.html | File | 19.76 KB | 0644 |
|
| pprint.html | File | 29.92 KB | 0644 |
|
| profile.html | File | 63.56 KB | 0644 |
|
| pty.html | File | 9.48 KB | 0644 |
|
| pwd.html | File | 11.43 KB | 0644 |
|
| py_compile.html | File | 11.12 KB | 0644 |
|
| pyclbr.html | File | 14.71 KB | 0644 |
|
| pydoc.html | File | 11.48 KB | 0644 |
|
| pyexpat.html | File | 71.53 KB | 0644 |
|
| python.html | File | 12.27 KB | 0644 |
|
| queue.html | File | 24.22 KB | 0644 |
|
| quopri.html | File | 11.9 KB | 0644 |
|
| random.html | File | 37.83 KB | 0644 |
|
| re.html | File | 134.74 KB | 0644 |
|
| readline.html | File | 28.24 KB | 0644 |
|
| repr.html | File | 20.43 KB | 0644 |
|
| resource.html | File | 26.48 KB | 0644 |
|
| restricted.html | File | 11.65 KB | 0644 |
|
| rexec.html | File | 37.41 KB | 0644 |
|
| rfc822.html | File | 42.22 KB | 0644 |
|
| rlcompleter.html | File | 13.51 KB | 0644 |
|
| robotparser.html | File | 12.27 KB | 0644 |
|
| runpy.html | File | 19.34 KB | 0644 |
|
| sched.html | File | 18.54 KB | 0644 |
|
| scrolledtext.html | File | 9.32 KB | 0644 |
|
| select.html | File | 39.67 KB | 0644 |
|
| sets.html | File | 36.92 KB | 0644 |
|
| sgi.html | File | 9.71 KB | 0644 |
|
| sgmllib.html | File | 30.77 KB | 0644 |
|
| sha.html | File | 12.09 KB | 0644 |
|
| shelve.html | File | 27.02 KB | 0644 |
|
| shlex.html | File | 32.1 KB | 0644 |
|
| shutil.html | File | 40.22 KB | 0644 |
|
| signal.html | File | 31.14 KB | 0644 |
|
| simplehttpserver.html | File | 18.41 KB | 0644 |
|
| simplexmlrpcserver.html | File | 31.39 KB | 0644 |
|
| site.html | File | 23.64 KB | 0644 |
|
| smtpd.html | File | 12.46 KB | 0644 |
|
| smtplib.html | File | 42.13 KB | 0644 |
|
| sndhdr.html | File | 10.02 KB | 0644 |
|
| socket.html | File | 106.34 KB | 0644 |
|
| socketserver.html | File | 59.83 KB | 0644 |
|
| someos.html | File | 15.11 KB | 0644 |
|
| spwd.html | File | 10.33 KB | 0644 |
|
| sqlite3.html | File | 139.5 KB | 0644 |
|
| ssl.html | File | 65.62 KB | 0644 |
|
| stat.html | File | 32.31 KB | 0644 |
|
| statvfs.html | File | 10.6 KB | 0644 |
|
| stdtypes.html | File | 260.4 KB | 0644 |
|
| string.html | File | 106.65 KB | 0644 |
|
| stringio.html | File | 18.81 KB | 0644 |
|
| stringprep.html | File | 16.13 KB | 0644 |
|
| strings.html | File | 14.93 KB | 0644 |
|
| struct.html | File | 40.88 KB | 0644 |
|
| subprocess.html | File | 84.91 KB | 0644 |
|
| sun.html | File | 6.84 KB | 0644 |
|
| sunau.html | File | 27.1 KB | 0644 |
|
| sunaudio.html | File | 17.79 KB | 0644 |
|
| symbol.html | File | 7.66 KB | 0644 |
|
| symtable.html | File | 22.94 KB | 0644 |
|
| sys.html | File | 98.7 KB | 0644 |
|
| sysconfig.html | File | 23.84 KB | 0644 |
|
| syslog.html | File | 17.92 KB | 0644 |
|
| tabnanny.html | File | 10.63 KB | 0644 |
|
| tarfile.html | File | 78.68 KB | 0644 |
|
| telnetlib.html | File | 25.48 KB | 0644 |
|
| tempfile.html | File | 29.42 KB | 0644 |
|
| termios.html | File | 16.01 KB | 0644 |
|
| test.html | File | 52.62 KB | 0644 |
|
| textwrap.html | File | 27.25 KB | 0644 |
|
| thread.html | File | 20.47 KB | 0644 |
|
| threading.html | File | 76.69 KB | 0644 |
|
| time.html | File | 56.93 KB | 0644 |
|
| timeit.html | File | 36.27 KB | 0644 |
|
| tix.html | File | 46.96 KB | 0644 |
|
| tk.html | File | 23.64 KB | 0644 |
|
| tkinter.html | File | 67.67 KB | 0644 |
|
| token.html | File | 19.62 KB | 0644 |
|
| tokenize.html | File | 18.45 KB | 0644 |
|
| trace.html | File | 25.54 KB | 0644 |
|
| traceback.html | File | 33.44 KB | 0644 |
|
| ttk.html | File | 101.75 KB | 0644 |
|
| tty.html | File | 9.06 KB | 0644 |
|
| turtle.html | File | 211.74 KB | 0644 |
|
| types.html | File | 27.59 KB | 0644 |
|
| undoc.html | File | 23.16 KB | 0644 |
|
| unicodedata.html | File | 18.55 KB | 0644 |
|
| unittest.html | File | 202.85 KB | 0644 |
|
| unix.html | File | 10.55 KB | 0644 |
|
| urllib.html | File | 58.68 KB | 0644 |
|
| urllib2.html | File | 100.58 KB | 0644 |
|
| urlparse.html | File | 40.41 KB | 0644 |
|
| user.html | File | 11.83 KB | 0644 |
|
| userdict.html | File | 29.73 KB | 0644 |
|
| uu.html | File | 11.03 KB | 0644 |
|
| uuid.html | File | 28.19 KB | 0644 |
|
| warnings.html | File | 46.6 KB | 0644 |
|
| wave.html | File | 22.22 KB | 0644 |
|
| weakref.html | File | 36.52 KB | 0644 |
|
| webbrowser.html | File | 23.07 KB | 0644 |
|
| whichdb.html | File | 8.85 KB | 0644 |
|
| windows.html | File | 9.33 KB | 0644 |
|
| winsound.html | File | 18.75 KB | 0644 |
|
| wsgiref.html | File | 81.04 KB | 0644 |
|
| xdrlib.html | File | 29.94 KB | 0644 |
|
| xml.dom.html | File | 89.04 KB | 0644 |
|
| xml.dom.minidom.html | File | 40.42 KB | 0644 |
|
| xml.dom.pulldom.html | File | 12.71 KB | 0644 |
|
| xml.etree.elementtree.html | File | 93.22 KB | 0644 |
|
| xml.html | File | 16.49 KB | 0644 |
|
| xml.sax.handler.html | File | 38.63 KB | 0644 |
|
| xml.sax.html | File | 20.22 KB | 0644 |
|
| xml.sax.reader.html | File | 39.09 KB | 0644 |
|
| xml.sax.utils.html | File | 14.26 KB | 0644 |
|
| xmlrpclib.html | File | 60.79 KB | 0644 |
|
| zipfile.html | File | 53.14 KB | 0644 |
|
| zipimport.html | File | 20.42 KB | 0644 |
|
| zlib.html | File | 25.46 KB | 0644 |
|