Jim Pivarski

### Discussed in https://github.com/scikit-hep/uproot5/discussions/948 Originally posted by **JacekHoleczek** August 24, 2023 I need to "move" (to here) my original StackOverflow topic: [How can I "dump" / get the content of...

This would be a major project, but it's frequently asked for. Users want to be able to do this: ```python with uproot.update("existing_file.root") as file: assert file["existing_tree"].num_entries == len(array) file["existing_tree"].new_branch(array) ```...

The issue raised in scikit-hep/uproot5#1116 is that @Jailbone's test case creates a TTree of `double[fixed_size]` (one fixed-size array per entry), and this should be read as a 2D NumPy array...

Especially in `uproot.dask`, where such use implies nested parallelism and the dangers of that. They shouldn't be very detailed results, since there isn't room for that in a single-line argument...

... but not as prolific.

Write tests for corner cases and fix the ones that are broken.

* `"fast"`: ignore binning metadata and just add counts arrays naively * `"adjust"`: the current behavior and future default; moves bin positions or creates bins (with zero content) to make...

This would replace the `_fromflatbuffers` pure-Python infrastructure with an extension module that uses C++ Flatbuffers generated code, bound to Python with pybind11. Objects made in Python and the `_toflatbuffers` methods...

I've seeded this branch with some hints about where and how to start. [Here](https://root.cern.ch/doc/master/classTH1.html) is the main documentation for ROOT's histograms, which includes 1D and 2D. (Note: the 2D histograms...