Create Column with ELIF in Pandas

Question

Question

I am having trouble figuring out how to create new DataFrame column based on the values in two other columns. I need to use if/elif/else logic. But all of the documentation and examples I have found only show if/else logic. Here is a sample of what I am trying to do:

Code

df['combo'] = 'mobile' if (df['mobile'] == 'mobile') elif (df['tablet'] =='tablet') 'tablet' else 'other')

I am open to using where() also. Just having trouble finding the right syntax.

Answer 1

In cases where you have multiple branching statements it's best to create a function that accepts a row and then apply it along the axis=1. This is usually much faster then iteration through rows.

def func(row):
    if row['mobile'] == 'mobile':
        return 'mobile'
    elif row['tablet'] =='tablet':
        return 'tablet' 
    else:
        return 'other'

df['combo'] = df.apply(func, axis=1)

Answer 2

I tried the following and the result was much faster. Hope it's helpful for others.

df['combo'] = 'other'
df.loc[df['mobile'] == 'mobile', 'combo'] = 'mobile'
df.loc[df['tablet'] == 'tablet', 'combo'] = 'tablet'