add leading zeroes python code example

Example 1: python convert number to string with leading zeros

str(1).zfill(2)
# 1 will be '01'

str(23).zfill(4)
# 23 will be '0023'

Example 2: python add zero to string

# add zeros to numbers
>>> n = 4
>>> print(f'{n:03}') # Preferred method, python >= 3.6
004
>>> print('%03d' % n)
004
>>> print(format(n, '03')) # python >= 2.6
004
>>> print('{0:03d}'.format(n))  # python >= 2.6 + python 3
004
>>> print('{foo:03d}'.format(foo=n))  # python >= 2.6 + python 3
004
>>> print('{:03d}'.format(n))  # python >= 2.7 + python3
004