Pandas - Dataframe.apply(lambad X: X Is Np.nan) Does Not Work

So basically a column in dataframe has Nan and float, I want to use apply to calculate the value in the column. If the value is nan, then return else, calculate. But looks like x i

Solution 1:

First things first. To get what you want:

df.A.isnull()

Secondly, np.nan is not comparable. By design np.nan == np.nan is False.

To get around this, pandas and numpy have specific functions to test if it is null. You could:

df.A.apply(pd.isnull)

But that is the same thing as:

df.A.isnull()

That I mentioned above.