python - Drop Upon Conditions -


i trying solve following problem: have dataframe. 1 of columns, have nan , numbers, distributed in random fashion. want drop lines based on column. criteria is: if line above 1 , 1 below have nan value, drop line. else, keep line in data frame.

this have managed to, quite sure wrong... appreciated!

i=0 while <= 500:     if (np.isnan(df.iloc[i+1]['column1'])) &  (np.isnan(df.iloc[i-1]['column1'])):         df2[i] = df.drop(df[i])

create sample data:

np.random.seed(0) df= pd.dataframe({'column1': np.random.randn(10)}) df.iloc[[2, 4, 7], 0] = np.nan >>> df     column1 0  1.764052 1  0.400157 2       nan 3  2.240893   # <<< drop. 4       nan 5 -0.977278 6  0.950088 7       nan 8 -0.103219 9  0.410599

apply filter.

>>> df[~((df['column1'].shift(1).isnull()) & (df['column1'].shift(-1).isnull()))]     column1 0  1.764052 1  0.400157 2       nan 4       nan 5 -0.977278 6  0.950088 7       nan 8 -0.103219 9  0.410599

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