When applied to a value, zfill() returns a value left-padded with zeros when the length of the initial 绳子 value less than that of the applied 宽度 value, otherwise, the initial 绳子 value as is.
句法:
str(string).zfill(width)
# Where string represents a string, an integer or a float, and
# width, the desired length to left-pad.