Python Patterns

I have now been working with Python for more than a month, here are some of the interesting patterns that I found in the language. Its a nice, clean and easy language, in particular I really enjoy the list comprehensions.

Lists

Loop over a list

for item in items:
        print item

Loop over a dictionary

for key, value in dictionaryname.items()

Map with list comprehensions

[func(item) for item in items]

Map over list of lists

[func(item) for list in lists for item in items]

Filter list

[item for item in items if wanted(item)]

Conditions in list comprehensions

#increase magnitude
    [item -1 if item < 0 else item + 1 for item in items]

Modules

Create a module

Create a folder with a blank file named init.py

Import classes from modules

from modulename import ClassName

Relative import or modules

from ..packagename import modulename

Debugging

Escape in to interpreter

import code
    code.interact(local=locals())

Benchmark

Simple Benchmark

from time import time
    t1 = time.time()
    function()
    t2 = time.time()
    print t2-t1

Exceptions

Raise an exception

raise Exception("message")

Useful built-in types: ValueError, TypeError, ArithmeticError. Complete List

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