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~~~ i = 0 while i < len(my_list): v = my_list[1] print(v) i += 1 ~~~ ~~~ for i in range(len(my_list)): v = my_list[i] print(v) ~~~ ~~~ for v in my_list: print(v) ~~~ #the for loop ~~~ for name in iterable: statements ~~~ #list -> elements ~~~ for e in [1,2,3,4]: print(e) ~~~ #strings ->characters ~~~ for c in 'hello': print(c) ~~~ #dicts -> keys ~~~ for k in {'a':1,'b':2}: print (k) ~~~ also ~~~ for v in d.itervalues(): pass for k,v in d.iteritems(): pass ~~~ #file -> lines ~~~ with open('filename') as f: for line in f: print repr(line) ~~~ #stdlib has interesting iterables ~~~ for match in re.finditer(pattern, string): pass for root, dirs, files in os.walk('/some/dir'): pass ~~~ ~~~ for num in itertools.count(): pass ~~~ #other users for iterables `new_list = list(iterable)` ~~~ results = [ f(x) for x in iterable ] total = sum(iterable) smallest = min(iterable) largest = max(iterable) ~~~ #get index enumerate() makes useful pairs ~~~ names = ['a','b','c'] list(enumerate(names)) ~~~ ``` [(0,'a'), (1,'b'), (2,'c') ] ``` ~~~ for num, name in enumerate(names): print(num, name) ~~~