str.
zfill
Pad strings in the Series by prepending ‘0’ characters.
Strings in the Series are padded with ‘0’ characters on the left of the string to reach a total string length width. Strings in the Series with length greater or equal to width are unchanged.
Differs from str.zfill() which has special handling for ‘+’/’-‘ in the string.
str.zfill()
Minimum length of resulting string; strings with length less than width be prepended with ‘0’ characters.
Series with ‘0’ left-padded strings.
Examples
>>> s = ps.Series(['-1', '1', '1000', np.nan]) >>> s 0 -1 1 1 2 1000 3 None dtype: object
Note that NaN is not a string, therefore it is converted to NaN. The minus sign in ‘-1’ is treated as a regular character and the zero is added to the left of it (str.zfill() would have moved it to the left). 1000 remains unchanged as it is longer than width.
>>> s.str.zfill(3) 0 0-1 1 001 2 1000 3 None dtype: object