Python enumerate () function usage

Source: Internet
Author: User
Tags python enumerate

Enumerate () is a built-in function in Python, using the method

Enumerate (X, [start=0])

The parameter X in a function can be an iterator (iterator) or a sequence, start is the starting count, and the default starts at 0.
X can be a dictionary, or it can be a sequence.

>>> a = {1:1, 2:2, 3:3}
>>> for I, item in enumerate (a):
...     Print I, item
ouput:
0 1
1 2
2 3
>>> B = [1,2,3,4,5,6]
>>> for I, item in enumerate (b):
...     Print I, item
ouput: 0 1 1 2 2 3 3 4 4 5 5 6
>>> for I, item in Enumerat E (b, start=10): ...     Print I, item
ouput:
1
2
3
4
5
15 6

Supplementary: Number of rows of statistical files
Learning from the Enumerate Usage Summary blog, enumerate can also be used to count the number of rows in a file to handle larger files.

Count = 0
file_count = open (filepath, ' R ')
for index, line in enumerate (file_count): 
    count = 1
Print Count
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