Python使用zip合并相鄰列表項的方法示例

本文實例講述了Python使用zip合并相鄰列表項的方法。分享給大家供大家參考，具體如下：
1》使用zip()函數和iter()函數，來合并相鄰的列表項
    
>>> x
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> zip(*[iter(x)]*2)
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> zip(*[iter(x)]*3)
[(1, 2, 3), (4, 5, 6), (7, 8, 9)]
>>> zip(*[iter(x)]*4)
[(1, 2, 3, 4), (5, 6, 7, 8)]

之所以會出現上述結果，是因為：    
>>> [iter(x)]*3
[<listiterator object at 0x02F4D790>, <listiterator object at0x02F4D790>, <listiterator object at 0x02F4D790>]

可以看到，列表中的3個迭代器實際上是同一個迭代器?。?！

2》   在1》的基礎上，封裝成一個函數，如下：    
>>> x
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> group_adjacent = lambda a, k: zip(*([iter(a)] * k))
>>> group_adjacent(x,3)
[(1, 2, 3), (4, 5, 6), (7, 8, 9)]
>>> group_adjacent(x,2)
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> group_adjacent(x,1)
[(1,), (2,), (3,), (4,), (5,), (6,), (7,), (8,), (9,)]

3》使用zip()函數和切片操作，來合并相鄰的表項    
>>> x
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> zip(x[::2],x[1::2])
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> zip(x[0::2],x[1::2])
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> zip(x[0::3],x[1::3],x[2::3])
[(1, 2, 3), (4, 5, 6), (7, 8, 9)]
>>> zip(x[::3],x[1::3],x[2::3])
[(1, 2, 3), (4, 5, 6), (7, 8, 9)]

4》  在3》的基礎上，封裝成函數，如下：
    
>>> x
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> group_adjacent = lambda a, k: zip(*[a[i::k] for i in range(k)])
>>> group_adjacent(x,3)
[(1, 2, 3), (4, 5, 6), (7, 8, 9)]
>>> group_adjacent(x,2)
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> group_adjacent(x,1)
[(1,), (2,), (3,), (4,), (5,), (6,), (7,), (8,), (9,)]