'GetBinError' option

[chrisstaude]

I'm looking for a way to add 'GetBinError' with uproot. Is there any possibility yet for matplotlib histograms?

[jpivarski]

You can get the values and errors from a histogram using values_errors. To get one bin from that, extract the element of the array.

(It's debatable whether histograms should have a method that only returns errors without also returning the values. Since the calculation of errors often involves calculating values, especially for profiles, such a method would usually be implemented by computing both and then throwing away the unwanted values. Not knowing this, users might think it's better to ask for values and errors separately, which would lead to a lot of wasted calculations.

Also, there's no value to extracting one bin, rather than an array of bins. For non-enormous histograms, the time needed to compute all bins in a vectorized way is about the same as the time needed to compute one bin because the bottleneck is executing Python instructions, not doing math. That only applies to non-enormous histograms—somewhere between millions and billions of bins.)