Hi I’m new in Root, and want to write and draw a histogram from a two (log base) column text file. I really appreciate your help.
VanDyke
Mytext…txt (465 Bytes)
Hi,
I propose you tackle the parsing of the ASCII following something along this lines: cplusplus.com/doc/tutorial/files/
And find inspiration about the usage of ROOT histograms having a look to these tutorials: root.cern/doc/master/group__tutorial__hist.html
Let us know if you encounter blockers with the ROOT part.
Cheers,
Danilo
I reformatted a bit your text file (remove tabs and aligned columns). Your file becomes:
1 6.12504e+14
1.25893 3.61421e+14
1.58489 2.17905e+14
1.99526 1.39038e+14
2.51189 9.13678e+13
3.16228 5.77759e+13
3.98107 3.26895e+13
5.01187 2.30892e+13
6.30957 1.25978e+13
7.94328 1.17648e+13
10 5.93986e+12
12.5893 3.40322e+12
15.8489 2.54676e+12
19.9526 1.29766e+12
25.1189 7.67923e+11
31.6228 3.89503e+11
39.8107 1.25781e+11
50.1187 4.13651e+10
63.0957 1.01185e+10
79.4328 1.52105e+09
100 1.44305e+08
125.893 9.3292e+06
158.489 142960
199.526 108.063
251.189 0
Then it is enough to do:
root [0] TGraph *g = new TGraph("Mytext.txt");
root [1] g->Draw();
That’s a graph, not an histogram, but given the layout of your data I thought it might be appropriate. From the graph you can retrieve the underlying histogram using g->GetHistogram().
I want to draw histogram with my txt file .what is command.file Name is events_MCH600.txt
Did you try the recipe given in this post ?
yes tried but error my file name is events_MCH600. txt and this file is in downloads I copies this file in my Analysis code. I want to draw histogram from this txt file so what’s command
Can you post this file ?
that file can not be shared heavy fie
Even a subset of it ?
I cannot do anything with a screen shot …
But the file you show looks like a xml file generated CompHEP.
Is it the case ?
Is there data inside you can read in a TGraph as this post suggests ?
Doing some google search pointed me to some links which might be of some help for you: https://theory.sinp.msu.ru/doku.php/comphep/extra/main
yes file generated from comphep actually file very heavy anyhows try to share but will be time taking
May be have a look at the link I posted. I think that’s what you need.
ok thanx