[SciPy-User] calculating the mean for each factor (like tapply in R)

Ben Temperton btemperton@gmail....
Tue Jul 31 22:28:22 CDT 2012

Hi there,

I've just moved from R to IPython and wondered if there was a good way of finding the means and/or variance of values in a dataframe given a factor

if df = 
x		experiment
10		1
13		1
12		1
3		2
4		2
6		2
33		3
44		3
55		3

in tapply you would do:

tapply(df$x, list(df$experiment), mean)
tapply(df$x, list(df$experiment), var)

I guess I can always loop through the array for each experiment type, but thought that this is the kind of functionality that would be included in a core library.

Many thanks,


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