Count indexes using “for” in Python

Question

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

Answer 1

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

Answer 2

This?

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

Answer 3

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

Answer 4

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

Answer 5

The most simple way I would be going for is;

i = -1
for step in my_list:
    i += 1
    print(i)

#OR - WE CAN CHANGE THE ORDER OF EXECUTION - SEEMS MORE REASONABLE

i = 0
for step in my_list:
    print(i) #DO SOMETHING THEN INCREASE "i"
    i += 1

Answer 6

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