zip函式：它是python的內建函式，(與序列有關的內建函式有：sorted()、reversed()、enumerate()、zip()),其中sorted()和zip()返回乙個序列(列表)物件，reversed()、enumerate()返回乙個迭代器(類似序列)
**一：
>>> name = ("
lilei
","lihua
","zhang")
>>> age = ("
21","
14","34"
)>>> for a,n in
zip(name,age):
...
print
a,n...
lilei 21lihua 14zhang 34
>>>
**二：
>>> all=>>> for i in
all.keys():
...
i,all[i]
...hell 20helo 23lei 19sony 15
>>>
**三：若傳入引數的長度不等，則返回list的長度和引數中長度最短的物件相同。
>>> aa = ("
1","
3","5"
)>>> bb = ("
ee","tt"
)>>> for a,n in
zip(aa,bb):
...
print
a,n...
1ee3tt
>>>zip(aa,bb)[('
1', '
ee'), ('
3', 'tt'
)]>>>
**四：zip()配合*號操作符,可以將已經zip過的列表物件解壓
>>>aa('
1', '
3', '5'
)>>>bb('
ee', 'tt'
)>>> ad =zip(aa,bb)
>>> zip(*ad)[('
1', '
3'), ('
ee', 'tt'
)]>>>zip(ad)
[(('
1', '
ee'),), (('
3', 'tt'
),)]
>>>
擴寬：
*二維矩陣變換（矩陣的行列互換）比如我們有乙個由列表描述的二維矩陣
a = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
通過python列表推導的方法，我們也能輕易完成這個任務
print [ [row[col] for row in a] for col in
range(len(a[0]))]
[[1, 4, 7], [2, 5, 8], [3, 6, 9]]
另外一種讓人困惑的方法就是利用zip函式：
>>> a = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
>>> zip(*a)
[(1, 4, 7), (2, 5, 8), (3, 6, 9)]
>>> map(list,zip(*a))
[[1, 4, 7], [2, 5, 8], [3, 6, 9]]
zip函式接受任意多個序列作為引數，將所有序列按相同的索引組合成乙個元素是各個序列合併成的tuple的新序列，新的序列的長度以引數中最短的序列為準。另外(*)操作符與zip函式配合可以實現與zip相反的功能，即將合併的序列拆成多個tuple。
①tuple的新序列
>>>>x=[1,2,3],y=['
a','
b','c'
]>>>zip(x,y)
[(1,'
a'),(2,'
b'),(3,'c'
)]②新的序列的長度以引數中最短的序列為準.
>>>>x=[1,2],y=['
a','
b','c'
]>>>zip(x,y)
[(1,'
a'),(2,'b'
)]③(*)操作符與zip函式配合可以實現與zip相反的功能,即將合併的序列拆成多個tuple。
>>>>x=[1,2,3],y=['
a','
b','c'
]>>>>zip(*zip(x,y))
[(1,2,3),('
a','
b','
c')]
高階應用：
1.zip打包解包列表和倍數>>> a = [1, 2, 3]
>>> b = ['
a', '
b', 'c'
]>>> z =zip(a, b)
>>>z
[(1, '
a'), (2, '
b'), (3, 'c'
)]>>> zip(*z)
[(1, 2, 3), ('
a', '
b', 'c'
)]2. 使用zip合併相鄰的列表項
>>> a = [1, 2, 3, 4, 5, 6]
>>> zip(*([iter(a)] * 2))
[(1, 2), (3, 4), (5, 6)]
>>> group_adjacent = lambda a, k: zip(*([iter(a)] *k))
>>> group_adjacent(a, 3)
[(1, 2, 3), (4, 5, 6)]
>>> group_adjacent(a, 2)
[(1, 2), (3, 4), (5, 6)]
>>> group_adjacent(a, 1)
[(1,), (2,), (3,), (4,), (5,), (6,)]
>>> zip(a[::2], a[1::2])
[(1, 2), (3, 4), (5, 6)]
>>> zip(a[::3], a[1::3], a[2::3])
[(1, 2, 3), (4, 5, 6)]
>>> group_adjacent = lambda a, k: zip(*(a[i::k] for i in
range(k)))
>>> group_adjacent(a, 3)
[(1, 2, 3), (4, 5, 6)]
>>> group_adjacent(a, 2)
[(1, 2), (3, 4), (5, 6)]
>>> group_adjacent(a, 1)
[(1,), (2,), (3,), (4,), (5,), (6,)]
3.使用zip和iterators生成滑動視窗 (n -grams)
>>> from itertools import
islice
>>> def
n_grams(a, n):
... z = (islice(a, i, none) for i in
range(n))
...
return zip(*z)
...>>> a = [1, 2, 3, 4, 5, 6]
>>> n_grams(a, 3)
[(1, 2, 3), (2, 3, 4), (3, 4, 5), (4, 5, 6)]
>>> n_grams(a, 2)
[(1, 2), (2, 3), (3, 4), (4, 5), (5, 6)]
>>> n_grams(a, 4)
[(1, 2, 3, 4), (2, 3, 4, 5), (3, 4, 5, 6)]
4.使用zip反轉字典
>>> m =
>>>m.items()[('
a', 1), ('
c', 3), ('
b', 2), ('
d', 4)]
>>>zip(m.values(), m.keys())
[(1, '
a'), (3, '
c'), (2, '
b'), (4, 'd'
)]>>> mi =dict(zip(m.values(), m.keys()))
>>>mi
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