Drawing data from ntuple

ROOT
1

hello every one ,
i have data in ntuple and i want to draw them in the same graph.
i wrote in the macro :
ntuple->Draw(“a:x”);
it works but i want to draw also b:x , c:x , d:x …
i tried
ntuple->Draw(“b:x”,“same”);
but it doesn’t work !!

any help please ?

2

ntuple->Draw(“b:x”, “”, “same”);
see: http://root.cern.ch/root/html/TTree.html#TTree:Draw@2

3

thank you so much ,

i want to ask about how can i change the maximum value of the y axis here in my case ?

4

Draw the variable that gives the widest y-axis range as the first. Then draw the rest using the “same” option.

5

Another option is to loop over all variables, get the maximum and minimum, and drawing a blank TH2F first with the right range and then drawing everything on top. This might be easier programmatically than trying to figure out which pair to draw first.

Cheers,
Charles

6

You could also try (but then the minimal value of the y-axis may be too high):
ntuple->Draw(“max(max(max(a, b), c), d):x”, “”, “axis”);
ntuple->Draw(“a:x”, “”, “same”);
ntuple->Draw(“b:x”, “”, “same”);
ntuple->Draw(“c:x”, “”, “same”);
ntuple->Draw(“d:x”, “”, “same”);

7

[quote=“Pepe Le Pew”]You could also try (but then the minimal value of the y-axis may be too high):
ntuple->Draw(“max(max(max(a, b), c), d):x”, “”, “axis”);
ntuple->Draw(“a:x”, “”, “same”);
ntuple->Draw(“b:x”, “”, “same”);
ntuple->Draw(“c:x”, “”, “same”);
ntuple->Draw(“d:x”, “”, “same”);[/quote]

I think it’s pretty clear that this doesn’t scale well. (Go ahead and write it up for 20 variables :slight_smile: ).

8

thaaank you , it works :smiley: