Hi Danilo,
Thanks for your reply! I have made some progress since my initial post. I feel I am very close to getting the result I need, but have been hung up on one problem.
To clarify, I have multiple ROOT files. Each file contains a canvas with several histograms like in the first post. From each canvas of the different ROOT files, I am trying to extract the same histogram and overlay them on one another. I am using pyROOT to accomplish this. My code currently looks like:
import ROOT
def overlay():
# List of predefined ROOT color constants
'''color_constants = [
ROOT.kBlack, ROOT.kWhite, ROOT.kRed, ROOT.kGreen, ROOT.kBlue,
ROOT.kYellow, ROOT.kMagenta, ROOT.kCyan, ROOT.kOrange, ROOT.kPink,
ROOT.kGray, ROOT.kAzure
]'''
i = 0
for run in range(1050, 1054, 2):
path = f"Baylor/root/local_runs/{run}_2023_HB3_ped.root"
print(f"Opening file: {path}")
# Select the file from which to extract histogram
file = ROOT.TFile.Open(path)
# Get the correct canvas from the file
canvas = file.Get("HB3Charge/HB3/HB3-2-Charge")
# Get the correct pad
pad = canvas.GetPad(26)
# Get the histogram
hist = pad.GetPrimitive("ChargeHB3-2-3-1")
# Print histogram statistics to verify content
print(f"Histogram entries: {hist.GetEntries()} for run {run}")
if hist.GetEntries() == 0:
print(f"Histogram is empty for run {run}")
continue
if i == 0:
new_canvas = ROOT.TCanvas("overlay_canvas", "Overlay of Histograms", 800,600)
hist.Draw()
else:
hist.Draw("SAME")
i += 1
file.Close()
new_canvas.Update()
new_canvas.SaveAs("testCanvas.jpg")
new_canvas.SaveAs("testCanvas.png")
new_canvas.SaveAs("testCanvas.pdf")
overlay()
What results is only the first histogram:
However, if I were to avoid using the loop and hard code the different root files, I (basically) get the kind of plot I’m looking for:
What is the deal here? For reference the code for the correct plot is:
import ROOT
def overlaytest():
file1 = ROOT.TFile.Open("Baylor/root/local_runs/1050_2023_HB3_ped.root")
file2 = ROOT.TFile.Open("Baylor/root/local_runs/1052_2023_HB3_ped.root")
canvas = file1.Get("HB3Charge/HB3/HB3-2-Charge") # HB3Charge/HB3/HB3-2-Charge_1/ChargeHB3-2-0-0 HB3Trend/HB_ADCvsBX
pad = canvas.GetPad(26)
h1 = pad.GetPrimitive("ChargeHB3-2-3-1")
h1.SetLineColor(ROOT.kRed)
canvas2 = file2.Get("HB3Charge/HB3/HB3-2-Charge")
pad2 = canvas2.GetPad(26)
h2 = pad2.GetPrimitive("ChargeHB3-2-3-1")
h2.SetLineColor(ROOT.kBlue)
# Check the type of the retrieved object
if isinstance(h1, ROOT.TH1):
print("The object retrieved is a histogram.")
new_canvas = ROOT.TCanvas("TEST", "imported canvas", 800,600)
h1.Draw()
h2.Draw("SAME")
# Legend things
legend = ROOT.TLegend(0.7, 0.7, 0.9, 0.9)
legend.AddEntry(h1, "Histogram 1", "l")
legend.AddEntry(h2, "Histogram 2", "l")
legend.Draw()
new_canvas.Update()
new_canvas.SaveAs("testCanvas1.jpg")
new_canvas.SaveAs("testCanvas1.png")
new_canvas.SaveAs("testCanvas1.pdf")
file1.Close()
overlaytest()
I could hardcode all the files, but there are many and I would much prefer to make the code more modular by using a loop, especially since all the file names are standardized.
Thanks!
–Ben