Hello everyone!
I am trying to make a histogramm from several .txt files. My plan is to make a macro that will read all ascii files and plot them in a histogram. To start, I tried to plot data from one .txt file, but I don’t to can!
My ascii file is
91.05363788568253 4
92.18552111171896 e
53.79679631716357 m
90.8046694021715 e
86.99876449534648 e
89.82364101505519 m
95.19489972604939 g
89.65891167531177 e
86.75620482372211 e
To plot, I use
TNtuple t("t","test","x:y");
t.ReadFile("Invariant_MassesNew.txt");
t.Draw("x","y==\"e\"");
but nothing is plotted! I can only plot if I delete the second column, but I want my histo to have data only if the second column is e or m or 4 or g.
What am I doing wrong?
Thank you in advance!
{
TTree t("t", "test");
t.ReadFile("Invariant_MassesNew.txt", "x/F:y/C");
t.Draw("x","y==\"e\"");
}
Thank you very much!!!
It is working!!!
The thing now is that I have a lot of ascii files.
How can I make a histo for each letter of the second column?
Assume that there are 10 .txt files each of them containing two column “data” as in my first post.
I want to plot in one histo the “e’s” and “m’s”(with different colors for each) and in another histo the “4’s” and “l’s”.
Is that possible?
Thank’s in advance! 
[code]{
TTree t(“t”, “test”);
t.ReadFile(“Invariant_Masses_0.txt”, “x/F:y/C”);
t.ReadFile(“Invariant_Masses_1.txt”);
t.ReadFile(“Invariant_Masses_2.txt”);
t.ReadFile(“Invariant_Masses_3.txt”);
t.ReadFile(“Invariant_Masses_4.txt”);
t.ReadFile(“Invariant_Masses_5.txt”);
t.ReadFile(“Invariant_Masses_6.txt”);
t.ReadFile(“Invariant_Masses_7.txt”);
t.ReadFile(“Invariant_Masses_8.txt”);
t.ReadFile(“Invariant_Masses_9.txt”);
TCanvas ch(“ch”, “ch”);
t.Draw(“x >> hh”, “”, “AXIS”);
t.Draw(“x >> h4”, "y==“4"”, “SAME”); h4->SetLineColor(1);
t.Draw(“x >> he”, “y==“e””, “SAME”); he->SetLineColor(2);
t.Draw(“x >> hg”, “y==“g””, “SAME”); hg->SetLineColor(3);
t.Draw(“x >> hm”, “y==“m””, “SAME”); hm->SetLineColor(4);
THStack s(“s”, “s”);
s.Add(h4);
s.Add(he);
s.Add(hg);
s.Add(hm);
TCanvas cs(“cs”, “cs”);
hh.Draw(“AXIS”);
s.Draw(“SAME”);
}[/code]
I tried to put your code in a root macro named plot.c
#include <cstdio>
#include <iostream>
#include <fstream>
# include "TROOT.h"
# include "TGraphErrors.h"
# include "TStyle.h"
# include "TMultiGraph.h"
# include "TF1.h"
# include "TLegend.h"
# include "TPaveStats.h"
# include "TArrow.h"
# include "TLatex.h"
# include "TPaveText.h"
# include "TText.h"
# include "TPavesText.h"
#include "TString.h"
#include "TSystem.h"
#include "TInterpreter.h"
#include "TFile.h"
#include "TH1.h"
#include "TNtuple.h"
#include "TCanvas.h"
void plot(){
TTree t("t", "test");
t.ReadFile("Invariant_Masses_0.txt", "x/F:y/C");
t.ReadFile("Invariant_Masses_1.txt");
t.ReadFile("Invariant_Masses_2.txt");
TCanvas ch("ch", "ch");
t.Draw("x >> hh", "", "AXIS");
t.Draw("x >> he", "y==\"e\"", "SAME"); he->SetLineColor(1);
THStack s;
s.Add(he);
TCanvas cs("cs", "cs");
hh->Draw("AXIS");
s.Draw("SAME");
}
But there isn’t any plot coming out!
I use this macro writing
In a “named macro”, you must use “pointers to objects” (e.g. “TTree *t” instead of “TTree t”), otherwise everything will be automatically deleted as soon as your macro terminates.
I used “TTree *t(“t”,“test”);” and I get the error
Syntax error.
Unless you mean something else.
I tried to compile it and it seems that TStack header was missing. I included it but I still don’t get a plot.
It says that he isn’t defined!
How about TTree *t = new TTree(“t”, “test”);
It says “.” is wrong so I changed it to “->” and I get a plot.
However there is an error about TStack
Error: Symbol TStack is not defined in current scope plot.c:60:
Error: type TStack not defined FILE:/home/thanos/Desktop/MC2013/./plot.c LINE:60
How about THStack *s = new THStack(“s”, “s”);
This is done already, like I did with all the “new items”(Canvas, File, Stack).
This error is appearing with THStack *s = new THStack(“s”, “s”);
Never mind…
I misspeled THStack with TStack… 
What is the difference between the plots in the canvas ch and cs?
