mirror of
https://github.com/github/codeql.git
synced 2025-12-24 20:56:33 +01:00
37 lines
1.3 KiB
XML
37 lines
1.3 KiB
XML
<!DOCTYPE qhelp PUBLIC
|
|
"-//Semmle//qhelp//EN"
|
|
"qhelp.dtd">
|
|
<qhelp>
|
|
<overview>
|
|
<p>The <code>for</code> statement is designed to allow you to iterate over the elements of a
|
|
sequence or other iterable object. If a non-iterable object is used in a <code>for</code> statement
|
|
(<code>for var in object:</code>) then a TypeError will be raised.
|
|
</p>
|
|
|
|
</overview>
|
|
<recommendation>
|
|
|
|
<p>Since this defect usually indicates a logical error, it is not possible to give a general method
|
|
for addressing the defect. </p>
|
|
|
|
</recommendation>
|
|
<example>
|
|
<p>
|
|
In this example, the loop may attempt to iterate over <code>None</code>, which is not an iterator.
|
|
It is likely that the programmer forgot to test for <code>None</code> before the loop.
|
|
</p>
|
|
<sample src="NonIteratorInForLoop.py" />
|
|
|
|
</example>
|
|
<references>
|
|
|
|
<li>Python Language Reference: <a href="http://docs.python.org/reference/compound_stmts.html#the-for-statement">The for statement</a>,
|
|
<a href="http://docs.python.org/2.7/reference/datamodel.html#object.__iter__">object.__iter__</a>.</li>
|
|
<li>Python Standard Library: <a href="http://docs.python.org/dev/library/stdtypes.html#iterator-types">Iterator types</a>.</li>
|
|
<li>Scipy lecture notes: <a href="http://scipy-lectures.github.io/advanced/advanced_python/#iterators">Iterators,
|
|
generator expressions and generators</a>.</li>
|
|
|
|
|
|
</references>
|
|
</qhelp>
|