pandas read in csv column as float and set empty cells to 0

Question

Is it possible to read in a CSV as a pandas DataFrame and set spaces (or empty cells) to 0 in one line? Below is an illustration of the problem.

Input:

Answer 1

Pandas will automatically read the empty values with NaN, so from there just fill them with the fillna method, setting the desired new value(in this case 0).

import pandas as pd

df = pd.read_csv('data.csv').fillna(value = 0)

Which yields:

     a  b    c
0  0.0  a  0.0
1  0.0  b  1.0
2  1.5  c  2.5
3  2.1  d  3.0

Also you can set different values for each column by passing a dict. Imagine we have the following csv file:

     a    b    c
0  NaN    a  0.0
1  0.0    b  1.0
2  1.5  NaN  2.5
3  2.1    d  NaN

If we want it to be the same as before we should do:

pd.read_csv('data.csv').fillna(value = {'a':0,'b':'c','c':3})

Yielding again:

     a  b    c
0  0.0  a  0.0
1  0.0  b  1.0
2  1.5  c  2.5
3  2.1  d  3.0