标签：
map()
Return an iterator that applies function to every item of iterable, yielding the results
例如：
a = map(lambda x:x**2 ,[1,2,3]) print([b for b in a])
结果：
[1, 4, 9]
或者：
a = map(lambda x,y:x+y ,[1,2,3],[1,2]) print([b for b in a])
结果：
[2, 4]
filter(function, iterable)
Construct an iterator from those elements of iterable for which function returns true.If function is None, all elements of iterable that are false are removed
例子：
a = filter(lambda x:x>2, [1,2,3]) print([b for b in a])
或者 function is None：
a = filter(None,[1,2,0,-1]) print([b for b in a])
结果：
[1, 2, -1]
zip()
Make an iterator that aggregates elements from each of the iterables
例子
x = [1, 2, 3] y = [4, 5, 6] zipped = zip(x, y) zipped = list(zipped) print(zipped)
结果
[(1, 4), (2, 5), (3, 6)]
dict()
>>> a = dict(one=1, two=2, three=3) >>> b = {‘one‘: 1, ‘two‘: 2, ‘three‘: 3} >>> c = dict(zip([‘one‘, ‘two‘, ‘three‘], [1, 2, 3])) >>> d = dict([(‘two‘, 2), (‘one‘, 1), (‘three‘, 3)]) >>> e = dict({‘three‘: 3, ‘one‘: 1, ‘two‘: 2}) >>> a == b == c == d == e True
一个综合的例子
a = map(lambda x: dict(zip([‘number‘], [x])),filter(lambda x: x > 3, [1,2,3,4,5,6])) print([b for b in a])
结果
[{‘number‘: 4}, {‘number‘: 5}, {‘number‘: 6}]
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原文地址：http://www.cnblogs.com/duyang/p/5236690.html
