Add Leading Zeros to Strings in Pandas Dataframe

Question

I have a pandas data frame where the first 3 columns are strings:

         ID        text1    text 2 0       2345656     blah      blah 1          3456     blah      blah 2        541304     blah      blah         3        201306       hi      blah         4   12313201308    hello      blah          

I want to add leading zeros to the ID:

                ID    text1    text 2 0  000000002345656     blah      blah 1  000000000003456     blah      blah 2  000000000541304     blah      blah         3  000000000201306       hi      blah         4  000012313201308    hello      blah  

I have tried:

df['ID'] = df.ID.zfill(15) df['ID'] = '{0:0>15}'.format(df['ID']) 

Answer 1

Try:

df['ID'] = df['ID'].apply(lambda x: '{0:0>15}'.format(x)) 

or even

df['ID'] = df['ID'].apply(lambda x: x.zfill(15)) 

Answer 2

str attribute contains most of the methods in string.

df['ID'] = df['ID'].str.zfill(15) 

See more: http://pandas.pydata.org/pandas-docs/stable/text.html