How to replace negative numbers in Pandas Data Frame by zero

Question

I would like to know if there is someway of replacing all DataFrame negative numbers by zeros?

Answer 1

Another clean option that I have found useful is pandas.DataFrame.mask which will "replace values where the condition is true."

Create the DataFrame:

In [2]: import pandas as pd

In [3]: df = pd.DataFrame({'a': [0, -1, 2], 'b': [-3, 2, 1]})

In [4]: df
Out[4]: 
   a  b
0  0 -3
1 -1  2
2  2  1

Replace negative numbers with 0:

In [5]: df.mask(df < 0, 0)
Out[5]: 
   a  b
0  0  0
1  0  2
2  2  1

Or, replace negative numbers with NaN, which I frequently need:

In [7]: df.mask(df < 0)
Out[7]: 
     a    b
0  0.0  NaN
1  NaN  2.0
2  2.0  1.0