Pandas

Recently I needed to identify which of the rows in a CSV file contained 0 values. This was interesting because normally I tend to look at this problem within columns rather than rows. Pandas provides a neat solution to this which I’ll demonstrate below using this data as an example:

import pandas as pd

d = {'a': [2,0,2,3,0,5, 9], 'b': [5,0,1,0,11,4,6]}
df = pd.DataFrame(d)

This data frame should look like this:

   a   b
0  0   0
1  2   1
2  3   0
3  0  11
4  5   4
5  9   6

Now, the final step to subset the data based on the existence of a 0 value within a row is to use the apply function and to look to see if a 0 is in the row values:

import pandas as pd

zero_rows_df = df[df.apply(lambda row: 0 in row.values, axis=1)]

That’s it! You should now have a dataframe containing only the 0 value rows:

   a   b
1  0   0
3  3   0
4  0  11