How do I select those rows of a DataFrame whose value in a column is none?
I've coded these to np.nan
and can't match against this type.
In [1]: import numpy as np In [2]: import pandas as pd In [3]: df = pd.DataFrame([[1, 2, 3], [3, 4, None]]) In [4]: df Out[4]: 0 1 2 0 1 2 3.0 1 3 4 NaN In [5]: df = df.fillna(np.nan) In [6]: df Out[6]: 0 1 2 0 1 2 3.0 1 3 4 NaN In [7]: df.iloc[1][2] Out[7]: nan In [8]: df.iloc[1][2] == np.nan Out[8]: False In [9]: df[df[2] == None] Out[9]: Empty DataFrame Columns: [0, 1, 2] Index: []
You can filter out rows with NAN value from pandas DataFrame column string, float, datetime e.t.c by using DataFrame. dropna() and DataFrame. notnull() methods. Python doesn't support Null hence any missing data is represented as None or NaN.
In order to check null values in Pandas DataFrame, we use isnull() function this function return dataframe of Boolean values which are True for NaN values. Code #1: Python.
you can use .isna() method:
In [48]: df[df[2].isna()] Out[48]: 0 1 2 1 3 4 NaN
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