How to pad a string with leading zeros in Python 3

python python-3.x math rounding
Gabby Freeland picture Gabby Freeland · Sep 9, 2016 · Viewed 107.6k times · Source

I'm trying to make length = 001 in Python 3 but whenever I try to print it out it truncates the value without the leading zeros (length = 1). How would I stop this happening without having to cast length to a string before printing it out?

Answer

nyedidikeke picture nyedidikeke · Sep 9, 2016

Make use of the zfill() helper method to left-pad any string, integer or float with zeros; it's valid for both Python 2.x and Python 3.x.

Sample usage:

print str(1).zfill(3);
# Expected output: 001

Description:

When applied to a value, zfill() returns a value left-padded with zeros when the length of the initial string value less than that of the applied width value, otherwise, the initial string value as is.

Syntax:

str(string).zfill(width)
# Where string represents a string, an integer or a float, and
# width, the desired length to left-pad.

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