Add Leading Zeros to Strings in Pandas Dataframe

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'])

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))

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

It can be achieved with a single line while initialization. Just use converters argument.

df = pd.read_excel('filename.xlsx', converters={'ID': '{:0>15}'.format})

so you'll reduce the code length by half :)

PS: read_csv have this argument as well.