Python zip()函數用法實例分析

本文實例講述了Python zip()函數用法。分享給大家供大家參考，具體如下：
這里介紹python中zip()函數的使用：    
>>> 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.

zip([seq1, ...])接受一系列可迭代對象作為參數，將對象中對應的元素打包成一個個元組，然后返回由這些元組組成的列表。若傳入參數的長度不等，則返回列表的長度和參數中長度最短的對象相同。

1》    
>>> x=[1,2,3]
>>> y=[1,2,3]
>>> z=(1,2,3)
>>> zip(x,y,z)
[(1, 1, 1), (2, 2, 2), (3, 3, 3)]

2》    
>>> x=(1,2,3,4)
>>> y=[1,2,3]
>>> zip(x,y) #傳入參數的長度不等，則返回列表的長度和參數中長度最短的對象相同
[(1, 1), (2, 2), (3, 3)]

3》    
>>> x
(1, 2, 3, 4)
>>> zip(x)
[(1,), (2,), (3,), (4,)]

4》    
>>> zip()
[]

5》zip()配合*號操作符,可以將已經zip過的列表對象解壓
    
>>> x=[1,2,3]
>>> y=['a','b','c']
>>> z=[4,5,6]
>>> xyz=zip(x,y,z)
>>> xyz
[(1, 'a', 4), (2, 'b', 5), (3, 'c', 6)]
>>> zip(*xyz)
[(1, 2, 3), ('a', 'b', 'c'), (4, 5, 6)]

6》
    
>>> x=[5,6,7]
>>> [x] #[x]生成一個列表的列表，它只有一個元素x
[[5, 6, 7]]
>>> [x]*3 #[x] * 3生成一個列表的列表，它有3個元素，[x, x, x]
[[5, 6, 7], [5, 6, 7], [5, 6, 7]]
>>> x
[5, 6, 7]
>>> zip(*[x]*3) #zip(* [x] * 3)等價于zip(x, x, x)
[(5, 5, 5), (6, 6, 6), (7, 7, 7)]

7》    
>>> name=['song','ping','python']
>>> age=[26,26,27]
>>> zip(name,age)
[('song', 26), ('ping', 26), ('python', 27)]
>>> for n,a in zip(name,age):
...   print n,a
...
song 26
ping 26
python 27