python zip()

>>> help(zip)

Help on built-in function zip in module __builtin__:

zip(...)

    zip(seq1 [, seq2 [...]]) -> [(seq1[0], seq2[0] ...), (...)]

    Return a list of tuples, where each tuple contains the i-th element

    from each of the argument sequences.  The returned list is truncated

    in length to the length of the shortest argument sequence.

>>> list_1 = ['name', 'age']

>>> list_2 = ['wang', 23]

>>> zip(list_1, list_2)

[('name', 'wang'), ('age', 23)]

>>> dict(zip(list_1, list_2))

{'age': 23, 'name': 'wang'}

如果两个参数不一样长，那么取短的。　　

也可以反向操作，见下面：

>>> list_3

{'age': 23, 'name': 'wang'}

>>> list_1 = ['name', 'age']

>>> list_2 = ['wang', 23]

>>> list_3 = zip(list_1, list_2)

>>> list_3

[('name', 'wang'), ('age', 23)]

>>> l1, l2 = zip(*list_3)

>>> list_1 == list(l1)

True

>>> type(l1)

<type 'tuple'>

>>> list_2 == l2

False

>>> list_2 == list(l2)

True

自然，也可以操作三个或者一个参数：

>>> zip(list_1)

[('name',), ('age',)]

>>> zip(list_1, list_2, l1)

[('name', 'wang', 'name'), ('age', 23, 'age')]

python.org的解释：

1. This function returns a list of tuples, where the i-th tuple contains the i-th element from each of the argument sequences or iterables. The returned list is truncated in length to the length of the shortest argument sequence. When there are multiple arguments which are all of the same length, zip() is similar to map() with an initial argument of None. With a single sequence argument, it returns a list of 1-tuples. With no arguments, it returns an empty list.

2. The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n).

3.zip() in conjunction with the * operator can be used to unzip a list

巴特西

python zip()

最新文章

热门文章