enumerate函数用于遍历序列中的元素以及它们的下标,多用于在for循环中得到计数,enumerate参数为可遍历的变量,如 字符串,列表等
一般情况下对一个列表或数组既要遍历索引又要遍历元素时,会这样写:
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for i in range ( 0 , len ( list )):
print i , list [i]
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但是这种方法有些累赘,使用内置enumerrate函数会有更加直接,优美的做法,先看看enumerate的定义:
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def enumerate (collection):
'Generates an indexed series: (0,coll[0]), (1,coll[1]) ...' i = 0 it = iter (collection)
while 1 :
yield (i, it. next ())
i + = 1
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enumerate会将数组或列表组成一个索引序列。使我们再获取索引和索引内容的时候更加方便如下:
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for index,text in enumerate ( list )):
print index ,text
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代码实例1:
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i = 0
seq = [ 'one' , 'two' , 'three' ]
for element in seq:
print i, seq[i]
i + = 1
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0 one
1 two
2 three
代码实例2:
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seq = [ 'one' , 'two' , 'three' ]
for i, element in enumerate (seq):
print i, seq[i]
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0 one
1 two
2 three
代码实例3:
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for i,j in enumerate ( 'abc' ):
print i,j
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0 a
1 b
2 c