Answers for "pandas fill column with value"

pandas fill na with value from another column

df['Cat1'].fillna(df['Cat2'])

pandas replace null values with values from another column

#Python
#Col 1 = where you want the values replaced
#Col 2 = where you want to take the values from
df["Col 1"].fillna(df["Col 2"], inplace=True)

python dataframe replace nan with 0

In [7]: df
Out[7]: 
          0         1
0       NaN       NaN
1 -0.494375  0.570994
2       NaN       NaN
3  1.876360 -0.229738
4       NaN       NaN

In [8]: df.fillna(0)
Out[8]: 
          0         1
0  0.000000  0.000000
1 -0.494375  0.570994
2  0.000000  0.000000
3  1.876360 -0.229738
4  0.000000  0.000000

how to fill whole column with same value in oandas

In [194]:
df['A'] = 'foo'
df

Out[194]:
     A
0  foo
1  foo
2  foo
3  foo