CODEWITHSUNDEEP
pythonfor-loopcountindexing
Lucas Rezende
Lucas Rezende

Reputation: 2686

Count indexes using "for" in Python

I need to do in Python the same as:

for (i = 0; i < 5; i++) {cout << i;}

but I don't know how to use FOR in Python to get the index of the elements in a list.

Upvotes: 47

Views: 149586

Answers (6)

dangerChihuahua007
dangerChihuahua007

Reputation: 20925

Just use 

for i in range(0, 5):
    print i

to iterate through your data set and print each value.

For large data sets, you want to use xrange, which has a very similar signature, but works more effectively for larger data sets. http://docs.python.org/library/functions.html#xrange

Upvotes: 22

alex
alex

Reputation: 1229

In additon to other answers - very often, you do not have to iterate using the index but you can simply use a for-each expression:

my_list = ['a', 'b', 'c']
for item in my_list:
    print item

Upvotes: 0

pkit
pkit

Reputation: 8301

If you have an existing list and you want to loop over it and keep track of the indices you can use the enumerate function. For example

l = ["apple", "pear", "banana"]
for i, fruit in enumerate(l):
   print "index", i, "is", fruit

Upvotes: 18

bgporter
bgporter

Reputation: 36564

use enumerate:

>>> l = ['a', 'b', 'c', 'd']
>>> for index, val in enumerate(l):
...    print "%d: %s" % (index, val)
... 
0: a
1: b
2: c
3: d

Upvotes: 10

Danny
Danny

Reputation: 7518

This?

for i in range(0,5): 
 print(i)

Upvotes: 0

Sven Marnach
Sven Marnach

Reputation: 602615

If you have some given list, and want to iterate over its items and indices, you can use enumerate():

for index, item in enumerate(my_list):
    print index, item

If you only need the indices, you can use range():

for i in range(len(my_list)):
    print i

Upvotes: 81

Related Questions