Checking if particular value (in cell) is NaN in pandas DataFrame not working using ix or iloc
Try this:
In [107]: pd.isnull(df.iloc[1,0])
Out[107]: True
UPDATE: in a newer Pandas versions use pd.isna():
In [7]: pd.isna(df.iloc[1,0])
Out[7]: True
The above answer is excellent. Here is the same with an example for better understanding.
>>> import pandas as pd
>>>
>>> import numpy as np
>>>
>>> pd.Series([np.nan, 34, 56])
0 NaN
1 34.0
2 56.0
dtype: float64
>>>
>>> s = pd.Series([np.nan, 34, 56])
>>> pd.isnull(s[0])
True
>>>
I also tried couple of times, the following trials did not work. Thanks to @MaxU
.
>>> s[0]
nan
>>>
>>> s[0] == np.nan
False
>>>
>>> s[0] is np.nan
False
>>>
>>> s[0] == 'nan'
False
>>>
>>> s[0] == pd.np.nan
False
>>>
pd.isna(cell_value)
can be used to check if a given cell value is nan. Alternatively, pd.notna(cell_value)
to check the opposite.
From source code of pandas:
def isna(obj):
"""
Detect missing values for an array-like object.
This function takes a scalar or array-like object and indicates
whether values are missing (``NaN`` in numeric arrays, ``None`` or ``NaN``
in object arrays, ``NaT`` in datetimelike).
Parameters
----------
obj : scalar or array-like
Object to check for null or missing values.
Returns
-------
bool or array-like of bool
For scalar input, returns a scalar boolean.
For array input, returns an array of boolean indicating whether each
corresponding element is missing.
See Also
--------
notna : Boolean inverse of pandas.isna.
Series.isna : Detect missing values in a Series.
DataFrame.isna : Detect missing values in a DataFrame.
Index.isna : Detect missing values in an Index.
Examples
--------
Scalar arguments (including strings) result in a scalar boolean.
>>> pd.isna('dog')
False
>>> pd.isna(np.nan)
True