Some improvements to RooStats tutorials, in particular Python versions

* Get rid of checks if files or objects in the file were found. It's
  ROOTs responsability to error out nicely if something is not found,
  not the responsability of the tutorials

* Use f-formatting in Python to be more concise

* Use Python iteration patters

* Use pythonic `len()` instead of `GetSize()`

* Use native Python string instead of `TString`

* In Python, one can retrieve objects in the `RooWorkspace with
  `workspace[obj_name]` independent of the type, which is preferred
  because it's more Pythonic

Author: guitargeek

tutorials/roostats/StandardProfileInspectorDemo.C

@@ -69,39 +69,21 @@ void StandardProfileInspectorDemo(const char *infile = "", const char *workspace
    } else
       filename = infile;
 
-   // Try to open the file
    TFile *file = TFile::Open(filename);
 
-   // if input file was specified but not found, quit
-   if (!file) {
-      cout << "StandardRooStatsDemoMacro: Input file " << filename << " is not found" << endl;
-      return;
-   }
-
    // -------------------------------------------------------
    // Tutorial starts here
    // -------------------------------------------------------
 
    // get the workspace out of the file
    RooWorkspace *w = (RooWorkspace *)file->Get(workspaceName);
-   if (!w) {
-      cout << "workspace not found" << endl;
-      return;
-   }
 
    // get the modelConfig out of the file
    ModelConfig *mc = (ModelConfig *)w->obj(modelConfigName);
 
    // get the modelConfig out of the file
    RooAbsData *data = w->data(dataName);
 
-   // make sure ingredients are found
-   if (!data || !mc) {
-      w->Print();
-      cout << "data or ModelConfig was not found" << endl;
-      return;
-   }
-
    // -----------------------------
    // now use the profile inspector
    ProfileInspector p;

tutorials/roostats/StandardProfileInspectorDemo.py

@@ -29,8 +29,6 @@
 ## \authors Akeem Hart, Kyle Cranmer (C++ Version)
 
 import ROOT
-import sys
-import math
 
 # -------------------------------------------------------
 # First part is just to access a user-defined file
@@ -50,13 +48,7 @@
     print("Done creating example input")
     print("---------------------\n\n")
 
-# Try to open the file
-try:
-    file = ROOT.TFile.Open(filename)
-except:
-    # if input file was specified but not found, quit
-    print("StandardRooStatsDemoMacro: Input file %s is not found" % filename)
-    sys.exit()
+file = ROOT.TFile.Open(filename)
 
 # -------------------------------------------------------
 # Tutorial starts here
@@ -65,39 +57,30 @@
 # get the workspace out of the file
 
 w = file.Get(workspaceName)
-if not w:
-    print("Workspace not found")
-    sys.exit()
 
 # get the modelConfig out of the file
-mc = w.obj(modelConfigName)
+mc = w[modelConfigName]
 
 # get the modelConfig out of the file
-data = w.data(dataName)
-
-# make sure ingredients are found
-if not data or not mc:
-    w.Print()
-    print("data or ModelConfig was not found")
-    sys.exit()
+data = w[dataName]
 
 # -----------------------------
 # now use the profile inspector
 p = ROOT.RooStats.ProfileInspector()
-list = p.GetListOfProfilePlots(data, mc)
+profile_plots = p.GetListOfProfilePlots(data, mc)
 
 # now make plots
 c1 = ROOT.TCanvas("c1", "ProfileInspectorDemo", 800, 200)
-n = list.GetSize()
+n = len(profile_plots)
 if n > 4:
-    nx = int(math.sqrt(n))
+    nx = int(n**0.5)
     ny = ROOT.TMath.CeilNint(n / nx)
-    nx = ROOT.TMath.CeilNint(math.sqrt(n))
+    nx = ROOT.TMath.CeilNint(n**0.5)
     c1.Divide(ny, nx)
 else:
     c1.Divide(n)
-for i in range(n):
+for i, plot in enumerate(profile_plots):
     c1.cd(i + 1)
-    list.At(i).Draw("al")
+    plot.Draw("al")
 
 c1.Update()

tutorials/roostats/StandardProfileLikelihoodDemo.C

@@ -91,36 +91,19 @@ void StandardProfileLikelihoodDemo(const char *infile = "", const char *workspac
    // Try to open the file
    TFile *file = TFile::Open(filename);
 
-   // if input file was specified byt not found, quit
-   if (!file) {
-      cout << "StandardRooStatsDemoMacro: Input file " << filename << " is not found" << endl;
-      return;
-   }
-
    // -------------------------------------------------------
    // Tutorial starts here
    // -------------------------------------------------------
 
    // get the workspace out of the file
    RooWorkspace *w = (RooWorkspace *)file->Get(workspaceName);
-   if (!w) {
-      cout << "workspace not found" << endl;
-      return;
-   }
 
    // get the modelConfig out of the file
    ModelConfig *mc = (ModelConfig *)w->obj(modelConfigName);
 
    // get the modelConfig out of the file
    RooAbsData *data = w->data(dataName);
 
-   // make sure ingredients are found
-   if (!data || !mc) {
-      w->Print();
-      cout << "data or ModelConfig was not found" << endl;
-      return;
-   }
-
    // ---------------------------------------------
    // create and use the ProfileLikelihoodCalculator
    // to find and plot the 95% confidence interval

tutorials/roostats/StandardProfileLikelihoodDemo.py

@@ -27,7 +27,6 @@
 ## \authors Akeem Hart, Kyle Cranmer (C++ Version)
 
 import ROOT
-import sys
 
 workspaceName = "combined"
 modelConfigName = "ModelConfig"
@@ -50,13 +49,7 @@
     print("Done creating example input")
     print("---------------------\n\n")
 
-# Try to open the file
-try:
-    file = ROOT.TFile.Open(filename)
-except:
-    # if input file was specified but not found, quit
-    print("StandardRooStatsDemoMacro: Input file %s is not found" % filename)
-    sys.exit()
+file = ROOT.TFile.Open(filename)
 
 # -------------------------------------------------------
 # Tutorial starts here
@@ -65,21 +58,12 @@
 # get the workspace out of the file
 
 w = file.Get(workspaceName)
-if not w:
-    print("Workspace not found")
-    sys.exit()
 
 # get the modelConfig out of the file
-mc = w.obj(modelConfigName)
+mc = w[modelConfigName]
 
 # get the modelConfig out of the file
-data = w.data(dataName)
-
-# make sure ingredients are found
-if not data or not mc:
-    w.Print()
-    print("data or ModelConfig was not found")
-    sys.exit()
+data = w[dataName]
 
 # ---------------------------------------------
 # create and use the ProfileLikelihoodCalculator
@@ -93,17 +77,8 @@
 
 # print out the interval on the first Parameter of Interest
 firstPOI = mc.GetParametersOfInterest().first()
-print(
-    "\n>>>> RESULT : "
-    + str(confLevel * 100)
-    + "% interval on "
-    + firstPOI.GetName()
-    + " is : ["
-    + str(interval.LowerLimit(firstPOI))
-    + ", "
-    + str(interval.UpperLimit(firstPOI))
-    + "]\n\n"
-)
+limit_lower, limit_upper = interval.LowerLimit(firstPOI), interval.UpperLimit(firstPOI)
+print(f"\n>>>> RESULT : {confLevel * 100}% interval on {firstPOI.GetName()} is : [{limit_lower}, {limit_upper}]\n")
 
 # make a plot
 
@@ -115,10 +90,10 @@
 plot.SetNPoints(nScanPoints)  # do not use too many points, it could become very slow for some models
 if poiXMin < poiXMax:
     plot.SetRange(poiXMin, poiXMax)
-opt = ROOT.TString("")
+opt = ""
 if plotAsTF1:
-    opt += ROOT.TString("tf1")
-plot.Draw(opt.Data())  # use option TF1 if too slow (plot.Draw("tf1")
+    opt += "tf1"
+plot.Draw(opt)  # use option TF1 if too slow (plot.Draw("tf1")
 
 # if requested perform also an hypothesis test for the significance
 if doHypoTest: