Python, pandas: how to remove greater than sign -

let's have following example dataframe

from pandas import series, dataframe df = dataframe({'a':['1', '<2', '3']}) 

i convert column string integer. in case of '<2', i'd take off '<' sign , put 1 (the closest integer less 2) in second row. what's efficient way that? example. actual data i'm working on has hundreds of thousands of rows. in advance.

you use series.apply:

import pandas pd df = pd.dataframe({'a':['1', '<2', '3']}) df['a'] = df['a'].apply(lambda x: int(x[1:])-1 if x.startswith('<') else int(x)) print(df.dtypes) #    int64 # dtype: object 

yields

print(df)    0  1 1  1 2  3  [3 rows x 1 columns]