[WIP]: Python commondata parser

[RosalynLP]

Addresses the first part of #379. In a similar vein to #404 we want to load in the commondata from file and parse it, converting to central values, systematics etc. This is to be done using pandas.

[RosalynLP]

So far I've implemented most of this, i.e.

• Created CommonData class
• parse_commondata parses a file to a CommonData
• load_commondata takes a CommonDataSpec and produces a CommonData using parse_commondata
• made test function in test_commondataparser.py

Still to do:

• Populate the CommonDataInfo object I created - do we actually need this though? I am not sure if it's that useful
• Error messages, e.g. raise a BadCommonDataError if parsing can't be done
• Similarly parse the systypes files
• Allow for >3 types of kinematics

[siranipour]

There is a problem at the moment that the commondata files start indexing from 1, while cuts objects start indexing from 0. This makes things a bit of a mess, so what's the verdict on indexing the dataframes from 0?

[RosalynLP]

There is a problem at the moment that the commondata files start indexing from 1, while cuts objects start indexing from 0. This makes things a bit of a mess, so what's the verdict on indexing the dataframes from 0?

Although I like the idea of indexing from 0 I worry that if someone were to identify point 224 for example, and then wanted to find that entry in the commondata file for whatever reason we'd want those two to match up. I'd think shifting the cuts would be best in this scenario.

[siranipour]

Yeah I worry both will probably be a bit of a mess, but your method less so. I'll do that in the next commit!

[RosalynLP]

Thanks @siranipour

[Zaharid]

This is rather unclear. It reads to me like it should be a list starting with zero.

[siranipour]

That is what we mean right? If datapoint 1 passed cuts then cuts = [0, ...

[siranipour]

What else is left for this PR?