<!DOCTYPE html PUBLIC
"-//W3C//DTD HTML 4.0 Transitional//EN">
<link rel=
"STYLESHEET" href=
"lib.css" type='text/css'
/>
<link rel=
"SHORTCUT ICON" href=
"../icons/pyfav.png" type=
"image/png" />
<link rel='start' href='../index.html' title='Python Documentation Index'
/>
<link rel=
"first" href=
"lib.html" title='Python Library Reference'
/>
<link rel='contents' href='contents.html'
title=
"Contents" />
<link rel='index' href='genindex.html' title='Index'
/>
<link rel='last' href='about.html' title='About this document...'
/>
<link rel='help' href='about.html' title='About this document...'
/>
<link rel=
"next" href=
"optparse-parsing-arguments.html" />
<link rel=
"prev" href=
"optparse-option-attributes.html" />
<link rel=
"parent" href=
"optparse-reference-guide.html" />
<link rel=
"next" href=
"optparse-parsing-arguments.html" />
<meta name='aesop' content='information'
/>
<title>6.21.3.6 Standard option types
</title>
<div id='top-navigation-panel' xml:id='top-navigation-panel'
>
<table align=
"center" width=
"100%" cellpadding=
"0" cellspacing=
"2">
<td class='online-navigation'
><a rel=
"prev" title=
"6.21.3.5 Option attributes"
href=
"optparse-option-attributes.html"><img src='../icons/previous.png'
border='
0' height='
32' alt='Previous Page' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"parent" title=
"6.21.3 Reference Guide"
href=
"optparse-reference-guide.html"><img src='../icons/up.png'
border='
0' height='
32' alt='Up One Level' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"next" title=
"6.21.3.7 Parsing arguments"
href=
"optparse-parsing-arguments.html"><img src='../icons/next.png'
border='
0' height='
32' alt='Next Page' width='
32'
/></A></td>
<td align=
"center" width=
"100%">Python Library Reference
</td>
<td class='online-navigation'
><a rel=
"contents" title=
"Table of Contents"
href=
"contents.html"><img src='../icons/contents.png'
border='
0' height='
32' alt='Contents' width='
32'
/></A></td>
<td class='online-navigation'
><a href=
"modindex.html" title=
"Module Index"><img src='../icons/modules.png'
border='
0' height='
32' alt='Module Index' width='
32'
/></a></td>
<td class='online-navigation'
><a rel=
"index" title=
"Index"
href=
"genindex.html"><img src='../icons/index.png'
border='
0' height='
32' alt='Index' width='
32'
/></A></td>
<div class='online-navigation'
>
<b class=
"navlabel">Previous:
</b>
<a class=
"sectref" rel=
"prev" href=
"optparse-option-attributes.html">6.21.3.5 Option attributes
</A>
<b class=
"navlabel">Up:
</b>
<a class=
"sectref" rel=
"parent" href=
"optparse-reference-guide.html">6.21.3 Reference Guide
</A>
<b class=
"navlabel">Next:
</b>
<a class=
"sectref" rel=
"next" href=
"optparse-parsing-arguments.html">6.21.3.7 Parsing arguments
</A>
<!--End of Navigation Panel-->
<H3><A NAME=
"SECTION0082136000000000000000"></A><A NAME=
"optparse-standard-option-types"></A>
6.21.3.6 Standard option types
<tt class=
"module">optparse
</tt> has six built-in option types:
<code>string
</code>,
<code>int
</code>,
<code>long
</code>,
<code>choice
</code>,
<code>float
</code> and
<code>complex
</code>. If you need to add new option
types, see section
<A HREF=
"#optparse-extending"><tex2html_cross_ref_visible_mark></A>, Extending
<tt class=
"module">optparse
</tt>.
Arguments to string options are not checked or converted in any way: the
text on the command line is stored in the destination (or passed to the
Integer arguments are passed to
<code>int()
</code> to convert them to Python
integers. If
<code>int()
</code> fails, so will
<tt class=
"module">optparse
</tt>, although with a more
useful error message. (Internally,
<tt class=
"module">optparse
</tt> raises OptionValueError;
OptionParser catches this exception higher up and terminates your
program with a useful error message.)
Likewise,
<code>float
</code> arguments are passed to
<code>float()
</code> for conversion,
<code>long
</code> arguments to
<code>long()
</code>, and
<code>complex
</code> arguments to
<code>complex()
</code>. Apart from that, they are handled identically to integer
<code>choice
</code> options are a subtype of
<code>string
</code> options. The
<code>choices
</code>
option attribute (a sequence of strings) defines the set of allowed
option arguments.
<code>optparse.check_choice()
</code> compares
user-supplied option arguments against this master list and raises
OptionValueError if an invalid string is given.
<div class='online-navigation'
>
<table align=
"center" width=
"100%" cellpadding=
"0" cellspacing=
"2">
<td class='online-navigation'
><a rel=
"prev" title=
"6.21.3.5 Option attributes"
href=
"optparse-option-attributes.html"><img src='../icons/previous.png'
border='
0' height='
32' alt='Previous Page' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"parent" title=
"6.21.3 Reference Guide"
href=
"optparse-reference-guide.html"><img src='../icons/up.png'
border='
0' height='
32' alt='Up One Level' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"next" title=
"6.21.3.7 Parsing arguments"
href=
"optparse-parsing-arguments.html"><img src='../icons/next.png'
border='
0' height='
32' alt='Next Page' width='
32'
/></A></td>
<td align=
"center" width=
"100%">Python Library Reference
</td>
<td class='online-navigation'
><a rel=
"contents" title=
"Table of Contents"
href=
"contents.html"><img src='../icons/contents.png'
border='
0' height='
32' alt='Contents' width='
32'
/></A></td>
<td class='online-navigation'
><a href=
"modindex.html" title=
"Module Index"><img src='../icons/modules.png'
border='
0' height='
32' alt='Module Index' width='
32'
/></a></td>
<td class='online-navigation'
><a rel=
"index" title=
"Index"
href=
"genindex.html"><img src='../icons/index.png'
border='
0' height='
32' alt='Index' width='
32'
/></A></td>
<div class='online-navigation'
>
<b class=
"navlabel">Previous:
</b>
<a class=
"sectref" rel=
"prev" href=
"optparse-option-attributes.html">6.21.3.5 Option attributes
</A>
<b class=
"navlabel">Up:
</b>
<a class=
"sectref" rel=
"parent" href=
"optparse-reference-guide.html">6.21.3 Reference Guide
</A>
<b class=
"navlabel">Next:
</b>
<a class=
"sectref" rel=
"next" href=
"optparse-parsing-arguments.html">6.21.3.7 Parsing arguments
</A>
<span class=
"release-info">Release
2.4.2, documentation updated on
28 September
2005.
</span>
<!--End of Navigation Panel-->
See
<i><a href=
"about.html">About this document...
</a></i> for information on suggesting changes.