Re: Obtaining the list of histograms in a root file

Laurent Aphecetche (Laurent.Aphecetche@subatech.in2p3.fr)
Wed, 02 Jun 1999 10:51:22 +0000

Giovanni Organtini wrote:
>
> Hi,
> I could not find this on the Web pages. I have a root file with several
> histograms. The number and the names of histograms varies from run to run.
> Is there a way to obtain the list of histograms (that I can see with ls())
> and/or directorie names inside a macro? Thank you.

Here's an example macro :

void loop(const char* filein="test.root")
{
TFile* fin = new TFile(filein) ;

if (!fin->IsOpen()) {
printf("<E> Cannot open input file %s\n",filein) ;
exit(1) ;
}

TList* list = fin->GetListOfKeys() ;
if (!list) { printf("<E> No keys found in file\n") ; exit(1) ; }
TIter next(list) ;
TKey* key ;
TObject* obj ;

while ( key = (TKey*)next() ) {
obj = key->ReadObj() ;
if ( (strcmp(obj->IsA()->GetName(),"TProfile")!=0)
&& (!obj->InheritsFrom("TH2"))
&& (!obj->InheritsFrom("TH1"))
) {
printf("<W> Object %s is not 1D or 2D histogram : "
"will not be converted\n",obj->GetName()) ;
}
printf("Histo name:%s title:%s\n",obj->GetName(),obj->GetTitle());
}
}

-- 
APHECETCHE Laurent (mailto:Laurent.Aphecetche@subatech.in2p3.fr)       
SUBATECH-Ecole des Mines de Nantes-4 rue Alfred Kastler-44070 NANTES
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TEL (+33/0) 2 51 85 84 17 - FAX (+33/0) 2 51 85 84 24
WWW: http://www-subatech.in2p3.fr/~photons