Fixed width number formatting python 3

Question

How do I get an integer to fill 0\'s to a fixed width in python 3.2 using the format attribute? Example:

a = 1
print(\'{0:3}\'.format(a))

gives

Answer 1

Prefix the width with a 0:

>>> '{0:03}'.format(1)
'001'

Also, you don't need the place-marker in recent versions of Python (not sure which, but at least 2.7 and 3.1):

>>> '{:03}'.format(1)
'001'

Answer 2

There is built-in string method .zfill for filling 0-s:

>>> str(42).zfill(5)
'00042'
>>> str(42).zfill(2)
'42'

Answer 3

Better:

number=12
print(f'number is equal to {number:03d}')