问题：获取Python FOR循环中的循环计数
在for遍历列表的Python 循环中，我们可以编写：
for item in list:
print item
整齐地遍历列表中的所有元素。有没有办法知道循环中到目前为止我循环了多少次？例如，我要列出一个列表，在处理完10个元素之后，我想对它们进行处理。
我想到的替代方案可能是这样的：
count=0
for item in list:
print item
count +=1
if count % 10 == 0:
print 'did ten'
要么：
for count in range(0,len(list)):
print list[count]
if count % 10 == 0:
print 'did ten'
是否有更好的方法（就像for item in list）来获得到目前为止的迭代次数？
In a Python for loop that iterates over a list we can write:
for item in list:
print item
and it neatly goes through all the elements in the list. Is there a way to know within the loop how many times I’ve been looping so far? For instance, I want to take a list and after I’ve processed ten elements I want to do something with them.
The alternatives I thought about would be something like:
count=0
for item in list:
print item
count +=1
if count % 10 == 0:
print 'did ten'
Or:
for count in range(0,len(list)):
print list[count]
if count % 10 == 0:
print 'did ten'
Is there a better way (just like the for item in list) to get the number of iterations so far?
回答 0
pythonic的方法是使用enumerate：
for idx,item in enumerate(list):
The pythonic way is to use enumerate:
for idx,item in enumerate(list):
回答 1
同意尼克。这是更详细的代码。
#count=0
for idx, item in enumerate(list):
print item
#count +=1
#if count % 10 == 0:
if (idx+1) % 10 == 0:
print 'did ten'
我已经在您的代码中注释掉了count变量。
Agree with Nick.
Here is more elaborated code.
#count=0
for idx, item in enumerate(list):
print item
#count +=1
#if count % 10 == 0:
if (idx+1) % 10 == 0:
print 'did ten'
I have commented out the count variable in your code.
回答 2
我知道一个比较老的问题，但是….发现其他东西，所以我投篮了：
[each*2 for each in [1,2,3,4,5] if each % 10 == 0])
I know rather old question but….came across looking other thing so I give my shot:
[each*2 for each in [1,2,3,4,5] if each % 10 == 0])
回答 3
使用zip函数，我们可以同时获取元素和索引。
countries = ['Pakistan','India','China','Russia','USA']
for index, element zip(range(0,countries),countries):
print('Index : ',index)
print(' Element : ', element,'\n')
output : Index : 0 Element : Pakistan ...
也可以看看 ：
Python.org
Using zip function we can get both element and index.
countries = ['Pakistan','India','China','Russia','USA']
for index, element zip(range(0,countries),countries):
print('Index : ',index)
print(' Element : ', element,'\n')
output : Index : 0 Element : Pakistan ...
See also :
Python.org
回答 4
尝试使用 itertools.count([n])
Try using itertools.count([n])
