Questions from Slido:

• What are the main benefits of uproot over pyroot? +24 -1
• Does opening a file with uproot4.open() read the whole content into memory directly, or does this only happen when specifying trees or branches? +16 -2
• Why don't we get rid of .root files altogether and switch to .hdf5? +17 -4
• When looking at TTree's in Uproot, you said that a TTree was also a Mapping - what does a Mapping mean? Is it just a dict? +8 -1
• Re:Uproot which parts of ROOT are I/O? Just TFile? Or canvasses and such? +11 -4
• Is the cache safe for the multithreading / multiprocessing out of the box? +9 -3
• Does uproot4 have all the features uproot3 has? +6 -2
• Can you say a little more about reading 'weird' objects in uproot? Particularly, what custom objects work out-of-the-box, what needs massaging, what won't work? +5 -1
• Is there any preference for the uproot and awkward compared to using the RDataFrame? Which one is preferred in which case? Thanks :) +4 -1
• .arrays() has the convenient "cuts" keyword argument, while .array() does not. Is this on purpose? +3
• Jim showed e.g. getting an array of the first element in the first 20 events with branch[:20, 0]. What happens if an event has no element in it? +5 -3
• line 57: the result is an array, which is not jagged anymore, but if there are elements with 0 sub-elements? Will there be a None or is the result just shorter? +2 -2
• Can we use uproot instead of using ROOT at all? Or are there some cases where ROOT is superior than uproot or pyroot? +5 -3
• Can we run any numpy based function under numba@jit? +3 -1
• are the cut strings parsed as c++ code? +3 -1
• using events = tree.arrays(library="ak", how="zip"), can you deal with eg different numbers of muons and electrons in the same "event"? +3 -1
• why do we have awkward arrays? cant we just open using normal arrays? and whats the difference between jagged, awkward and normal arrays? (edited) +3 -1
• Is iterating over arrays fast in python? I thought python always gets really slow if one uses loops +4 -2
• Are the TTree array alias formulas the same as TFormulas like in TTree::Draw? Or some other syntax? +4 -3
• how you convert root-file to numpy array if your ntuple has different length of branching (for example, pt of tracks in each vertex, which is varied). +2 -2
• How hard is it to write code that's as performant as uproot from C++ and ROOT? Is someone who is proficient at C++ and ROOT at a disadvantage? If so, how? +1
• using iterate, can you control the size of the "chunk" or is it the defined cache? +2 -1
• Do you need to manually clear the cache or does it vacate itself when full and you need more? +1 -1
• what are the main benefits of uproot over ROOT? +3 -2
• Can uproot do everything that ROOT does? What are the limitations of using uproot? +2 -2
• Is it possible to create a hierarchy of directories with histograms inside? +1 -1
• If one needs to incorporate methods where multiple dataframes/arrays need to be loaded into memory to make histograms what is the optimal way to do this? 0
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