Overwriting Nan values with .loc in Pandas [duplicate]

I tried to solve the required task with the following code line:

df['Age'][np.isnan(df["Age"])] = rand1

But this raises a "SettingWithCopyWarning" and I think locating the Nan values in the dataframe (Column 'Age') by using the .loc feature might be a better way of doing this.

I already took a look at the documentation, but still don't know how I can fix this problem. Couldn't find any solutions on here with .loc either.

I would appreciate any hints and advice.

1 Answer

You need fillna for replace NaN to some value:

df.Age = df.Age.fillna(rand1) 

Your solution with loc:

df.loc[np.isnan(df["Age"]), 'Age'] = rand1 #same as #df.loc[df["Age"].isnull(), 'Age'] = rand1 

You can also check indexing view versus copy.

Sample:

df = pd.DataFrame({'Age':[20,23,np.nan]}) print (df) Age 0 20.0 1 23.0 2 NaN rand1 = 30 df.Age = df.Age.fillna(rand1) print (df) Age 0 20.0 1 23.0 2 30.0 

#if need cast to int df.Age = df.Age.fillna(rand1).astype(int) print (df) Age 0 20 1 23 2 30