Filling a Histogram from a text file

ROOT
1

Hello,

I currently have a text file (attached), from which I need to draw data and fit in a histogram. The fitting part I know how to do, but I am having trouble extracting the data from the .txt and drawing it in a histogram. I’ve got two versions of my code, neither of which really work.

This one draws only the first event:

[quote]
TTree NoiseTree = new TTree(“NoiseTree”, “NoiseTree”);
NoiseTree->ReadFile("/11_noPreamble.txt", “mV”);
TH1F NoiseHist = new TH1F(“Signal And Noise”, “Signal And Noise”, 200, -160, 40);
NoiseTree->Draw(“mV>>NoiseHist”);[/quote]

While this one draws the first event, and a few value=0 events it gets from I don’t know where:

[quote]TTree NoiseTree = new TTree(“NoiseTree”, “NoiseTree”);
NoiseTree->ReadFile("/11_noPreamble.txt", “mV”);
TH1F NoiseHist = new TH1F(“Signal And Noise”, “Signal And Noise”, 200, -160, 40);
int entries = NoiseTree.GetEntry();
for(int i = 0; i < entries; i++) {
NoiseHist->Fill(NoiseTree.GetEntry(i));
}
NoiseHist->Draw();[/quote]

The problem is that the file has 20,000 events, and thus the histogram should be quite a bit bigger than one event. Does anyone know how to get the code to draw every event?
11_noPreamble.txt (117 KB)

2

Execute: sed -i -e 's/[\r\t]/\n/g' 11_noPreamble.txt

3

Did that. Got a whole bunch of “____ not defined in current scope”. I don’t think it will work, not that I know what it does.

If possible, I’d prefer solutions involving code. I have a lot of files to perform this procedure on, having to manually enter commands on the command line would make things difficult.

4

The command that I gave you is NOT a ROOT command. You need to execute it directly in your shell prompt (then enter ROOT again and execute your own macro).

5

That seems to have worked. Thank you very much. Would you mind explaining to me what that command did?

6

For instance you can google “sed linux command tutorial”… you will get many details
or just type “man sed” at the linux prompt…