Python Enumerate()用法及代码示例

很多时候，在处理迭代器时，我们还需要保留迭代次数。 Python通过提供内置函数enumerate()来简化程序员的任务。
Enumerate()方法向可迭代对象添加一个计数器，并以枚举对象的形式返回它。然后，可以直接在for循环中使用此枚举对象，或使用list()方法将其转换为元组列表。

用法:

enumerate(iterable, start=0)

参数：
Iterable:any object that supports iteration
Start:the index value from which the counter is 
              to be started, by default it is 0

# Python program to illustrate 
# enumerate function 
l1 = ["eat","sleep","repeat"] 
s1 = "geek"
  
# creating enumerate objects 
obj1 = enumerate(l1) 
obj2 = enumerate(s1) 
  
print "Return type:",type(obj1) 
print list(enumerate(l1)) 
  
# changing start index to 2 from 0 
print list(enumerate(s1,2))

输出：

Return type:
[(0, 'eat'), (1, 'sleep'), (2, 'repeat')]
[(2, 'g'), (3, 'e'), (4, 'e'), (5, 'k')]

Using Enumerate object in loops

# Python program to illustrate 
# enumerate function in loops 
l1 = ["eat","sleep","repeat"] 
  
# printing the tuples in object directly 
for ele in enumerate(l1):
    print ele 
print 
# changing index and printing separately 
for count,ele in enumerate(l1,100):
    print count,ele

输出：

(0, 'eat')
(1, 'sleep')
(2, 'repeat')

100 eat
101 sleep
102 repeat

相关用法

注：本文由纯净天空筛选整理自 Enumerate() in Python。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。