Re: list of unique values from a TTree

Hello Rob,

On Fri, May 25, 2012 at 2:08 PM, Rob Mahurin <rob_at_jlab.org> wrote:
>
>        2. Why is this (and the equivalent GetEntry loop called from
>           CINT) so much slower that tree.Draw("scandata1")?
>

A workaround for this might be to use something along the following (unfortunately) multi line snippet:

tree.Draw("scandata1>>h", "goff")
v1 = tree.GetV1() # gets an array of value you jsut drew set(v1[n] for n in xrange(tree.GetEntries())

I think the reason things are so much slower from python is because ROOT was written as a C++ library with a pretty nifty python interface bolted on afterwards, instead of being written in C++ as a python library from the get go.

Tim

-- 
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