GetBinWithFirstEntry (?)

Is there a function in root which returns the bin number that has the first entry, or the x axis position which has the first entry?

I’ve tried browsing the TH1F and TF1 classes on the ref guide, but can’t seem to find it …

Thanks

I’m not an expert and surely you have solved but I try anyway.

I do not understand what “bin containing first entry” means.
If you mean “the bin containing the first value used to fill the histo” I don’t
think it can be retrieved.

Regards, Germano

It means “the first bin with a non-null entry”

Rene

Hi, thanks for the response, but yeah you guessed i’ve figured it out.

Rene was right its the first non null bin entry.

I couldn’t find such a function in Root, so I just wrote a little function to include in my program.

int GetFirstNon0Entry(TH1F *h)
{
     int nbins = h->GetXbins();
     int binconent = 0;
     int x=0;
     
     for (int i=0; i<nbins; i++)
         {
               bincontent = h -> GetBinContent(i+1);
               if (bincontent !=0)
               {
                      x= h -> GetBinCenter(i+1);
                      return (x);
         }
}

then where i needed the x co-ordinate of the first non-null entry i called the function:

int first_time = GetFirstNon0Entry( histogram );

Thanks anyway Germano :slight_smile:

[quote=“no1else”]Hi, thanks for the response, but yeah you guessed i’ve figured it out.

Rene was right its the first non null bin entry.

Thanks anyway Germano :slight_smile:[/quote]

Not at all.
I wonder only if it could be guessed by your post that you was referring
to the first non null bin entry, or I missed some other information.

But I’m happy you solved :wink:

Cheers, Germano