Converting single column text files into TH1F for fitting

[tk231]

Hi!

I’m not very well-versed in C/C++ and I was hoping someone could point me in the right direction:

I’ve got a .dat file which contains only a column of counts, each coming from a specific channel. I intend to read this .dat file and save it as a TH1F .root file, which each row corresponding to a TH1F bin.

I have read Rene Brun’s basic.c and basic2.c, but I can’t seem to get it to work. I have also heard that TGraphs can read text files natively and am not adverse to first reading them in as TGraphs and then converting it into a TH1D (for future fitting).

Thanks in advance for any pointers!

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ROOT Version: 6.09/01
Platform: Linux Mint 19.1
Compiler: Not Provided

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[Wile_E_Coyote]

Filling Histograms with a text file

Try: /* Usage examples: root [0] .L Am241.cxx root [1] Am241(); // expects "Am241.txt" in the current directory root [1] Am241("/full/path/to/some/Am241.txt"); or simply: root [0] .x Am241.cxx root [0] .x Am241.cxx("/full/path/to/some/Am241.txt") */ #include "TGraph.h" #include <fstream> void Am241(const char *file = "Am241.txt") { if ((!file) || (!file[0])) return; // just a precaution TGraph *g = new TGraph(); g->SetTitle("Count Rate;N_{counts};# occurencies"); double y;…

BTW. There exists the TGraph::Fit method.

[tk231]

Thanks! It worked!

And thank you for the tip about the TGraph::Fit method!