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An Introduction to Python

Guido van Rossum
Fred L. Drake, Jr., editor
Python Software Foundation
November 2006 (Release 2.5)

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(1) Actually, call by object reference would be a better description, since if a mutable object is passed, the caller will see any changes the callee makes to it (items inserted into a list).

(2) The rules for comparing objects of different types should not be relied upon; they may change in a future version of the language.

(3) In fact function definitions are also `statements' that are `executed'; the execution enters the function name in the module's global symbol table.

(4) Except for one thing. Module objects have a secret read-only attribute called __dict__ which returns the dictionary used to implement the module's namespace; the name __dict__ is an attribute but not a global name. Obviously, using this violates the abstraction of namespace implementation, and should be restricted to things like post-mortem debuggers.

(5) Python will execute the contents of a file identified by the ‘PYTHONSTARTUP’ environment variable when you start an interactive interpreter.

(6) http://www.wide.ad.jp/about/index.html

(7) This requires the operator module. Type import operator; help(operator); for details.

ISBN 0954161769An Introduction to PythonSee the print edition