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| * Loops may have else clauses for code executed after normal termination (not a break). | * Loops may have else clauses for code executed after normal termination (not a break). | ||
| - | ===== Assorted ===== | + | ===== Assorted |
| * Dictionaries are unordered sets of key value pairs e.g. { a:1, b:2} or dict([(a, | * Dictionaries are unordered sets of key value pairs e.g. { a:1, b:2} or dict([(a, | ||
| * Dictionary keys/ | * Dictionary keys/ | ||
| + | * sorted and reversed take in liats and return new lists. | ||
| + | * enumerate takes in a list and returns a list of pairs where the first item in the pair is an integer starting with 0. | ||
| + | * zip takes two or more lists with the same number of elements and creates a single list of lists with corresponding members grouped together. | ||
| + | |||
| + | ===== Modules & Packages ===== | ||
| + | |||
| + | * A //module// is a file of python definitions. | ||
| + | * Definitions in a module can be accessed by importing the module. <code python> | ||
| + | from fib import fib1, fib2 | ||
| + | </ | ||
| + | * __name__ is set to the name of the module or to __main__ if called from the command line. | ||
| + | * The search list for modules is the variable sys.path initialized from the directory containing the input script (or the current directory), PYTHONPATH and the installation-dependent default. | ||
| + | * When a module is imported, a byte-code version is stored to module.pyc which speeds up successive loads. | ||
| + | * There are many standard modules including sys which is common to all platforms. | ||
| + | * dir(module) lists all names in a module sorted alphabetically. dir(builtins) shows all the built-in functions and variables. | ||
| + | * Packages can be used to group modules. Packages should be in a named directory with an __init__.py file optionally containing initialization code. E.g. import sound.effects.echo . | ||
| + | * . is the current package, .. is the parent package etc. | ||