Display number with leading zeros

Question

How do I display a leading zero for all numbers with less than two digits?

1    →  01
10   →  10
100  →  100

Answer 1

In Python 2 (and Python 3) you can do:

number = 1
print("%02d" % (number,))

Basically % is like printf or sprintf (see docs).

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For Python 3.+, the same behavior can also be achieved with format:

number = 1
print("{:02d}".format(number))

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For Python 3.6+ the same behavior can be achieved with f-strings:

number = 1
print(f"{number:02d}")