Calculating mean of column in dataframe with conditions

Question

I have a dataframe with 2 columns, 'A' and 'B', both consisting of values between 0 and 1.

How do I, for example, calculate the mean of the values in column 'B' when the value in column 'A' is between 0 and 0.1, ignoring the other values?

Quang Hoang · Accepted Answer · 2020-08-04 13:50:20Z

3

You can use boolean indexing:

df.loc[df['A'].between(0,0.1), 'B'].mean()

Or in this case, since the values are already >=0, you can just do:

df.loc[df['A'].le(0.1), 'B'].mean()

answered Aug 4, 2020 at 13:50

Quang Hoang

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