Using lambda if condition to column based on value of another column in Pandas dataframe

Question

Let's consider a dataframe like this:

(index)    condition    number
0          'increase'   1
1          'do-nothing' 1

I'd like to increment the elements in the number column if the condition element in the same row is equal to 'increase'. In principle, I thought about something similar:

# non-working example
df['number'] = df['number'].apply(lambda x: x+=1 if x['condition'] == 'increase' else x)

This example of course does not work. Is there an efficient method to do it?

Answer 1

I think you're looking for:

df.loc[df['condition'] == 'increase', 'number'] += 1