Read a .txt file and create a graph

[naikal_mc]

Hello, I am trying to read a file with 9 columns to create an TGraphAsymmErrors.
I was using:

ifstream infile;
infile.open(“data.txt”);

but it is getting too complicated and the code wasn’t working. I want to read all 9 columns. Can someone tell me an easier way to do this?

ps.: I also want to have the values of the graph to calculate some other quantities, so it’s not useful to use:

TGraph MyGraph = new TGraph(“MyData.txt”);
MyGraph->Draw("A");

because I need the data.

[couet]

@naikal_mc

ps.: I also want to have the values of the graph to calculate some other quantities, so it’s not useful to use:

TGraph MyGraph = new TGraph(“MyData.txt”);
MyGraph->Draw("A");

because I need the data.

You can easily retrieve the data in a TGraph using GetX and GetY

[ksmith]

You may also want to investigate TTree::ReadFile.