python - pandas dataframe drop columns by number of nan -

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i have dataframe columns containing nan. i'd drop columns number of nan. example, in following code, i'd drop column 2 or more nan. in case, column 'c' dropped , 'a' , 'b' kept. how can implement it?

import pandas pd import numpy np  dff = pd.dataframe(np.random.randn(10,3), columns=list('abc')) dff.iloc[3,0] = np.nan dff.iloc[6,1] = np.nan dff.iloc[5:8,2] = np.nan  print dff

there thresh param dropna, need pass length of df - number of nan values want threshold:

in [13]:  dff.dropna(thresh=len(dff) - 2, axis=1) out[13]:                   b 0  0.517199 -0.806304 1 -0.643074  0.229602 2  0.656728  0.535155 3       nan -0.162345 4 -0.309663 -0.783539 5  1.244725 -0.274514 6 -0.254232       nan 7 -1.242430  0.228660 8 -0.311874 -0.448886 9 -0.984453 -0.755416

so above drop column not meet criteria of length of df (number of rows) - 2 number of non-na values.


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