Re: Save a histogram as a text file on disk

Hello Ida,

>From what I see in your script, you could have also used
myHist->GetBinLowEdge(i) and myHist->GetBinLowEdge(i+1), or myHist->GetBinLowEdge(i)+myHist->GetBinWidth(i). Casting to (double) is not necessary, the methods you use anyway return Double_t.

Have fun

        Eduard

On Tue, 27 Sep 2011, Ida Häggström wrote:

> Hello Eduard and thanks for your help!
> I've managed to do what I wanted with your tips... Here's my code snippet if
> anyone else is interested:
> ----------
> //Save histogram as text file
> ofstream myFile("histogram.txt");
> myFile << "BinNo" << "\t"<< "Start" << "\t"<< "End" << "\t"<< "No" << endl;
> for (Int_t i=1; i<=myHist->GetNbinsX();i++) {
> myFile << i << "\t" <<
> (double)(myHist->GetBinCenter(i))-(double)(myHist->GetBinWidth(i)/2.) <<
> "\t" <<
> (double)(myHist->GetBinCenter(i))+(double)(myHist->GetBinWidth(i)/2.) <<
> "\t" << (double)myHist->GetBinContent(i) << endl;
> }
> myFile.close();
> ----------
> Cheers, Ida
>
> On Tue, Sep 27, 2011 at 9:45 AM, Eduard Avetisyan
> <Eduard.Avetisyan_at_desy.de>wrote:
>
> >
> > Hi Ida,
> >
> > Try this:
> > // Start at 1 (not 0) as bin 0 is the underflow, you probably don't need it
> > for (Int_t i=1; i<myHist->GetNbinsX();i++) {
> > cout << i << " " << myHist->GetBinContent(i) << endl;
> > }
> >
> > If you need not the bin number but the value, replace 'i' with
> > myHist->GetBinCenter(i).
> >
> > Cheers
> > Eduard
> >
> > On Tue, 27 Sep 2011, Ida Häggström wrote:
> >
> > > Dear Rooters,
> > >
> > > I'm making a little script that stores data in a histogram. Now I want to
> > > save this data as a text file (to open in another program, e.g. Matlab)
> > with
> > > bin in one column and number in a second column. I cannot really find any
> > > examples of this in the users guide... Is there a good way to do this?
> > Below
> > > are some relevant pieces of my code. Thanks!
> > > /Ida
> > >
> > > ----------------------
> > > TH1F *myHist= new TH1F("myHist","Sensitivity",100,-200.,+200.);
> > >
> > > for (Int_t i=0; i<nentries;i++) {
> > > //Long loop...
> > > myHist->Fill(z);
> > > }
> > > ----------------------
> > >
> >
>
Received on Tue Sep 27 2011 - 13:32:36 CEST