{
"cells": [
{
"cell_type": "markdown",
"id": "36174c26",
"metadata": {},
"source": [
"# loopdir\n",
"Example script to loop over all the objects of a ROOT file directory and print in\n",
"Postscript all the TH1 derived objects.\n",
"This script uses the file generated by tutorial hsimple.C\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Rene Brun \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:14 PM."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "4a1b3a06",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:14:28.517694Z",
"iopub.status.busy": "2026-05-19T20:14:28.517563Z",
"iopub.status.idle": "2026-05-19T20:14:29.131673Z",
"shell.execute_reply": "2026-05-19T20:14:29.131139Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
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},
"metadata": {},
"output_type": "display_data"
},
{
"name": "stderr",
"output_type": "stream",
"text": [
"Info in : ps file hsimple.ps has been created\n",
"Info in : Current canvas added to ps file hsimple.ps\n",
"Info in : Current canvas added to ps file hsimple.ps\n",
"Info in : Current canvas added to ps file hsimple.ps\n",
"Info in : ps file hsimple.ps has been closed\n"
]
}
],
"source": [
"TFile *f1 = TFile::Open(\"hsimple.root\");\n",
"TIter keyList(f1->GetListOfKeys());\n",
"TKey *key;\n",
"TCanvas c1;\n",
"c1.Print(\"hsimple.ps[\");\n",
"while ((key = (TKey*)keyList())) {\n",
" TClass *cl = gROOT->GetClass(key->GetClassName());\n",
" if (!cl->InheritsFrom(\"TH1\")) continue;\n",
" TH1 *h = (TH1*)key->ReadObj();\n",
" h->Draw();\n",
" c1.Print(\"hsimple.ps\");\n",
"}\n",
"c1.Print(\"hsimple.ps]\");"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "ROOT C++",
"language": "c++",
"name": "root"
},
"language_info": {
"codemirror_mode": "text/x-c++src",
"file_extension": ".C",
"mimetype": " text/x-c++src",
"name": "c++"
}
},
"nbformat": 4,
"nbformat_minor": 5
}