pythonpandasdataframe

How do I replace all the instances of a certain character in a dataframe?

I have a dataframe that has many instances of '?' in different rows with dtype 'object'.

How can I replace all the '?' with 0.

Solution

  • Consider the dataframe df

    df = pd.DataFrame([['?', 1], [2, '?']])

print(df)

   0  1
0  ?  1
1  2  ?

    replace 

    df.replace('?', 0)

   0  1
0  0  1
1  2  0

    mask or where 

    df.mask(df == '?', 0)
# df.where(df != '?', 0)

   0  1
0  0  1
1  2  0

    However, imagine your dataframe has ? within longer strings.

    df = pd.DataFrame([['a?', 1], [2, '?b']])

print(df)

    0   1
0  a?   1
1   2  ?b

    replace with regex=True 

    df.replace('\?', '0', regex=True)

    0   1
0  a0   1
1   2  0b