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

Here is a simple example to show you what is going on:

import pandas as pd
import numpy as np

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

lengths = df.apply(lambda x: len(x[0]))
mask = lengths < 15

print df
print lengths
print mask
print df[mask]

Results in:

                 0                1                 2                 3 
0   0.315649003654   -1.20005871043  -0.0973557747322  -0.0727740019505 
1  -0.270800223158   -2.96509489589    0.822922470677     1.56021584947 
2   -2.36245475786  0.0763821870378      1.0540009757   -0.452842084388 
3   -1.03486927366  -0.269946751202   0.0611709385483   0.0114964425747 

0    14 
1    14 
2    16 
3    16 
dtype: int64 

0     True 
1     True 
2    False 
3    False 
dtype: bool 

                 0               1                 2                 3 
0   0.315649003654  -1.20005871043  -0.0973557747322  -0.0727740019505 
1  -0.270800223158  -2.96509489589    0.822922470677     1.56021584947