np.where Not Working in my Pandas

Question

I have an np.where problem using Pandas that is driving me crazy and I can\'t seem to solve through Google, the documentation, etc.

I\'m hoping someone has insight.

Answer 1

You need to pass the boolean mask and the (two) values columns:

np.where(Full_Names_Test_2['MarketCap'] == 'n/a', 7)
# should be
np.where(Full_Names_Test_2['MarketCap'] == 'n/a', Full_Names_Test_2['MarketCap'], 7)

See the np.where docs.

or alternatively use the where Series method:

Full_Names_Test_2['MarketCap'].where(Full_Names_Test_2['MarketCap'] == 'n/a', 7)