Value_counts in RDataFrame

Newbie
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1

Dear experts,

I am trying to implement something analogue to what value_counts() does in pandas with RDataFrame. I have found this previous entry where they ask for precisely this:

I have one minor question: Is there a function which is able to count the occurrence of values within a specific column? Lets say I apply a filter and have column called ‘event_nr’.

And the answer pointed to

For example you can Aggregate column values into a std::map value → count.

and I have tried to use it to obtain the value counts, but I haven’t been able to. Could someone provide an example in PyROOT?

ROOT Version: 6.36.04

Best,

Lidia.

2

Hi @lidia,

Thank you for your post. Adding @vpadulan and @mczurylo to this thread who can help with your question.

Best,
Lukas