[FIXED] new column(s) in a pandas dataframe based on values calculated from rest of the columns

Issue

I am struggling with figuring out how to return a conditional value to a column based on values in selected columns on same index row. see the attached picture.

1. I have a df where "<0" column is supposed to count the number of instances in previous 18 columns where valueas are less than 0.

2. I also need to count the total number of columns excluding NaN for each row.

any suggestions?

Solution

You can use:

s1 = df.lt(0).sum(axis=1)
s2 = df.notna().sum(axis=1)

df['<0'] = s1
df['TotCount (ex Nan)'] = s2

Or:

cols = df.columns

df['<0'] = df[cols].lt(0).sum(axis=1)
df['TotCount (ex Nan)'] = df[cols].notna().sum(axis=1)

Answered By - mozway