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| 55 | <H3><A NAME="SECTION0043101000000000000000"></A><A NAME="typesmodules"></A> |
| 56 | <BR> |
| 57 | 2.3.10.1 Modules |
| 58 | </H3> |
| 59 | |
| 60 | <P> |
| 61 | The only special operation on a module is attribute access: |
| 62 | <code><var>m</var>.<var>name</var></code>, where <var>m</var> is a module and <var>name</var> |
| 63 | accesses a name defined in <var>m</var>'s symbol table. Module attributes |
| 64 | can be assigned to. (Note that the <tt class="keyword">import</tt> statement is not, |
| 65 | strictly speaking, an operation on a module object; <code>import |
| 66 | <var>foo</var></code> does not require a module object named <var>foo</var> to exist, |
| 67 | rather it requires an (external) <em>definition</em> for a module named |
| 68 | <var>foo</var> somewhere.) |
| 69 | |
| 70 | <P> |
| 71 | A special member of every module is <tt class="member">__dict__</tt>. |
| 72 | This is the dictionary containing the module's symbol table. |
| 73 | Modifying this dictionary will actually change the module's symbol |
| 74 | table, but direct assignment to the <tt class="member">__dict__</tt> attribute is not |
| 75 | possible (you can write <code><var>m</var>.__dict__['a'] = 1</code>, which |
| 76 | defines <code><var>m</var>.a</code> to be <code>1</code>, but you can't write |
| 77 | <code><var>m</var>.__dict__ = {}</code>). Modifying <tt class="member">__dict__</tt> directly |
| 78 | is not recommended. |
| 79 | |
| 80 | <P> |
| 81 | Modules built into the interpreter are written like this: |
| 82 | <code><module 'sys' (built-in)></code>. If loaded from a file, they are |
| 83 | written as <code><module 'os' from |
| 84 | '/usr/local/lib/python2.4/os.pyc'></code>. |
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| 122 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> |
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