How can I select Pandas.DataFrame by elements' length

Question

How can I select Pandas.DataFrame by elements\' length.

import pandas as pd;
import numpy as np;

df=pd.DataFrame(np.random.randn(4,4).astype(str))

df.apply(lam         


        

Answer 1

You could take advantage of the vectorized string operations available under .str, instead of using apply:

>>> df.applymap(len)
    0   1   2   3
0  19  18  18  21
1  20  18  19  18
2  18  19  20  18
3  19  19  18  18
>>> df[1].str.len()
0    18
1    18
2    19
3    19
Name: 1, dtype: int64
>>> df.loc[df[1].str.len() == 19]
                     0                    1                     2                   3
2   0.2630843312551179  -0.4811731811687397  -0.04493981407412525  -0.378866831599991
3  -0.5116348949042413  0.07649572869385729    0.8899251802216082  0.5802762385702874