In Python, how to specify a format when converting int to string?

Question

In Python, how do I specify a format when converting int to string?

More precisely, I want my format to add leading zeros to have a string with constant length. For

Answer 1

With python3 format and the new 3.6 f"" notation:

>>> i = 5
>>> "{:4n}".format(i)
'   5'
>>> "{:04n}".format(i)
'0005'
>>> f"{i:4n}"
'   5'
>>> f"{i:04n}" 
'0005'