Recursion Error when Accessing Histograms from Root File using uproot in a Jupyter Notebook

Question

I've made root files with histograms through another program, and I'm trying to extract this histograms in a Jupyter notebook using Python3 to do various bits of analysis on these histograms.

In the past, this has been a non-issue, but I'm on a new device and things have been wonky.

I have a root file named root_file.root located at /location and inside this root file are a number of TDirectories. If numbers are important, the histograms I'm trying to access are 5 layers of TDirectories in, which I'll label as tdir, and the histogram as root_hist

My imports:

import numpy as np
import matplotlib.pyplot as plt
import math
import pandas as pd
import uproot

To open this file I've been using

file = uproot.open("/location/root_file.root")

I can then use file.keys() to see all the various histograms and TDirectories within the root file. I can get myself all the way to the point where I can see the histogram I want to access through file['tdir'].keys() and one of the keys is 'root_hist'. I can even run file['tdir'].classnames() and see that 'root_hist' is a TH2F.

The issue is that then when I try to actually access the histogram thought hist = file['tdir']['root_hist'] I get a Recursion Error (note that test[key0] is the same thing as file['tdir']['root_hist'] where test=file['tdir'] and key0='root_hist'):

RecursionError                            Traceback (most recent call last)
Input In [27], in <cell line: 7>()
      5 print(test.keys())
      6 print(key0)
----> 7 test[key0].all_members

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:2089, in ReadOnlyDirectory.__getitem__(self, where)
   2087     else:
   2088         last = step
-> 2089         step = step[item]
   2091 elif isinstance(step, uproot.behaviors.TBranch.HasBranches):
   2092     return step["/".join(items[i:])]

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:2089, in ReadOnlyDirectory.__getitem__(self, where)
   2087     else:
   2088         last = step
-> 2089         step = step[item]
   2091 elif isinstance(step, uproot.behaviors.TBranch.HasBranches):
   2092     return step["/".join(items[i:])]

    [... skipping similar frames: ReadOnlyDirectory.__getitem__ at line 2089 (2966 times)]

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:2089, in ReadOnlyDirectory.__getitem__(self, where)
   2087     else:
   2088         last = step
-> 2089         step = step[item]
   2091 elif isinstance(step, uproot.behaviors.TBranch.HasBranches):
   2092     return step["/".join(items[i:])]

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:2072, in ReadOnlyDirectory.__getitem__(self, where)
   2070 if item != "":
   2071     if isinstance(step, ReadOnlyDirectory):
-> 2072         if ":" in item and item not in step:
   2073             index = item.index(":")
   2074             head, tail = item[:index], item[index + 1 :]

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:1922, in ReadOnlyDirectory.__contains__(self, where)
   1920 def __contains__(self, where):
   1921     try:
-> 1922         self.key(where)
   1923     except KeyError:
   1924         return False

File ~/Library/Python/3.8/lib/python/site-packages/uproot/reading.py:2014, in ReadOnlyDirectory.key(self, where)
   2000 def key(self, where):
   2001     """
   2002     Returns a ``TKey`` (:doc:`uproot.reading.ReadOnlyKey`) for the object
   2003     selected by ``where``.
   (...)
   2012     Note that this does not read any data from the file.
   2013     """
-> 2014     where = uproot._util.ensure_str(where)
   2016     if "/" in where:
   2017         items = where.split("/")

File ~/Library/Python/3.8/lib/python/site-packages/uproot/_util.py:67, in ensure_str(x)
     63 def ensure_str(x):
     64     """
     65     Ensures that ``x`` is a string (decoding with 'surrogateescape' if necessary).
     66     """
---> 67     if isinstance(x, bytes):
     68         return x.decode(errors="surrogateescape")
     69     elif isinstance(x, str):

RecursionError: maximum recursion depth exceeded while calling a Python object

I don't understand myself to be doing any recursion here, but it is a consistent error that I get. I've tried upping the limit on recursion, but end up crashing my kernel before solving the problem. I can find no documentation that leads me to believe I'm trying to access the histogram in any way other than the intended method

Where am I going wrong?

Answer 1

Problem Resolved! The issue was the histogram name from my root file has a : in it, which is treated differently between uproot3 and 4. So to use the old way I can just pip install uproot3 and import that instead, but I'm probably going to simply change my histogram names to be able to use the more updated version.