how to index in for loop python code example

Example 1: python gt index in for cycle

my_list = [0,1,2,3,4]
for idx, val in enumerate(my_list):
    print('{0}: {1}'.format(idx,val))
#This will print:
#0: 0
#1: 1
#2: 2
#...

Example 2: python for loop index

# Creates two variables; An index (num), and the value at that index (line)
for num, line in enumerate(lines):
    print("{0:03d}: {}".format(num, line))