[RF] Add and refactor printContents() for RooAbsData

roofit/roofitcore/inc/RooAbsData.h

@@ -236,6 +236,9 @@ class RooAbsData : public TNamed, public RooPrintable {
 
   Int_t defaultPrintContents(Option_t* opt) const override ;
 
+  /// Print the contents of the dataset to the specified output stream.
+  virtual void printContents(std::ostream& os = std::cout) const = 0;
+
   void setDirtyProp(bool flag) ;
 
   double moment(const RooRealVar& var, double order, const char* cutSpec=nullptr, const char* cutRange=nullptr) const ;

roofit/roofitcore/inc/RooDataHist.h

@@ -139,7 +139,9 @@ class RooDataHist : public RooAbsData, public RooDirItem {
   void printMultiline(std::ostream& os, Int_t content, bool verbose=false, TString indent="") const override;
   void printArgs(std::ostream& os) const override;
   void printValue(std::ostream& os) const override;
-  void printDataHistogram(std::ostream& os, RooRealVar* obs) const;
+
+  /// Print the contents of the dataset to the specified output stream.
+  void printContents(std::ostream& os = std::cout) const override;
 
   void SetName(const char *name) override;
   void SetNameTitle(const char *name, const char* title) override;

roofit/roofitcore/inc/RooDataSet.h

@@ -102,6 +102,9 @@ class RooDataSet : public RooAbsData, public RooDirItem {
   void printArgs(std::ostream& os) const override;
   void printValue(std::ostream& os) const override;
 
+  /// Print the contents of the dataset to the specified output stream.
+  void printContents(std::ostream& os = std::cout) const override;
+
   void SetName(const char *name) override;
   void SetNameTitle(const char *name, const char* title) override;
 

roofit/roofitcore/src/RooDataHist.cxx

@@ -2303,13 +2303,49 @@ void RooDataHist::printMultiline(ostream& os, Int_t content, bool verbose, TStri
   }
 }
 
-void RooDataHist::printDataHistogram(ostream& os, RooRealVar* obs) const
+/**
+ * \brief Prints the contents of the RooDataHist to the specified output stream.
+ *
+ * This function iterates through all bins of the histogram and prints the
+ * coordinates of each bin, along with its weight and statistical error.
+ * It is designed to be robust, handling empty or invalid datasets,
+ * and works for histograms of any dimension.
+ *
+ * \param os The output stream (e.g., std::cout) to write the contents to.
+ */
+void RooDataHist::printContents(std::ostream& os) const
 {
-  for(Int_t i=0; i<obs->getBins(); ++i){
-    this->get(i);
-    obs->setBin(i);
-    os << this->weight() << " +/- " << this->weightSquared() << std::endl;
-  }
+    os << "Contents of RooDataHist \"" << GetName() << "\"" << std::endl;
+
+    if (numEntries() == 0) {
+        os << "(dataset is empty)" << std::endl;
+        return;
+    }
+
+    for (int i = 0; i < numEntries(); ++i) {
+        const RooArgSet* obs = get(i); // load i-th bin
+        os << "  Bin " << i << ": ";
+
+        bool first = true;
+        for (const auto* var : *obs) {
+            if (!first) os << ", ";
+            first = false;
+
+            os << var->GetName() << "=";
+            if (auto realVar = dynamic_cast<const RooRealVar*>(var)) {
+                os << realVar->getVal();
+            } else if (auto catVar = dynamic_cast<const RooCategory*>(var)) {
+                os << catVar->getCurrentLabel();
+            } else {
+                os << "(unsupported type)"; //added as a precaution
+            }
+        }
+
+        double lo, hi;
+        weightError(lo, hi, RooAbsData::SumW2);
+        os << ", weight=" << weight() << " +/- [" << lo << "," << hi << "]"
+           << std::endl;
+    }
 }
 
 

roofit/roofitcore/src/RooDataSet.cxx

@@ -1689,3 +1689,58 @@ void RooDataSet::loadValuesFromSlices(RooCategory &indexCat, std::map<std::strin
       _dstore->loadValues(sliceData->store(), cutVar, rangeName);
    }
 }
+
+/**
+ * \brief Prints the contents of the RooDataSet to the specified output stream.
+ *
+ * This function iterates through all events (rows) of the dataset and prints
+ * the value of each observable, along with the event's weight.
+ * It is designed to be robust, handling empty or invalid datasets gracefully,
+ * and works for datasets of any dimension.
+ *
+ * \param os The output stream (e.g., std::cout) to write the contents to.
+ */
+void RooDataSet::printContents(std::ostream& os) const
+{
+    os << "Contents of RooDataSet \"" << GetName() << "\"" << std::endl;
+
+    if (numEntries() == 0) {
+        os << "(dataset is empty)" << std::endl;
+        return;
+    }
+
+    if (get() == nullptr || get()->empty()) {
+        os << "(dataset has no observables)" << std::endl;
+        return;
+    }
+
+    for (int i = 0; i < numEntries(); ++i) {
+        const RooArgSet* row = get(i); // reuses internal buffers
+        os << "  Entry " << i << ": ";
+
+        bool first = true;
+        for (const auto* var : *row) {
+            if (!first) os << ", ";
+            first = false;
+
+            os << var->GetName() << "=";
+            if (auto realVar = dynamic_cast<const RooRealVar*>(var)) {
+                os << realVar->getVal();
+            } else if (auto catVar = dynamic_cast<const RooCategory*>(var)) {
+                os << catVar->getLabel();
+            } else {
+                os << "(unsupported type)"; //added as a precaution
+            }
+        }
+
+        os << ", weight=" << weight();
+
+        double lo, hi;
+        weightError(lo, hi);
+        if (lo != 0.0 || hi != 0.0) {
+            os << " ±[" << lo << "," << hi << "]";
+        }
+
+        os << std::endl;
+    }
+}