解析复杂的基于字符串的配置选项

Question

I'm trying to build a Python program that will parse the conversion codes from a Universe Database. These conversion codes are highly dense strings that encode a ton of information, and I'm struggling to get started. The different permutations of the conversion codes likely number in the hundreds of thousands (though I haven't done the math).

I'm familiar with argparse , however I can't come up with a way of handling this kind of parsing with argparse , and my Google-fu hasn't come up with any other solution.

Initially, my lazy work around was to just do a dictionary lookup for the most common conversion codes, but now that we're using this Python program for more data, it's becoming a huge chore to maintain each individual conversion code.

For example, date conversion codes may take forms like:

• Date: D[n][*m][s][fmt[[f1, f2, f3, f4, f5]]][E][L] , eg D2/ or D4-2/RM
• Datetime: DT[4|D|4D|T|TS|Z][;timezone] , eg DTZ or DT4;America/Denver
• Datetime ISO: DTI[B][R|W][S][Z][2|1|0][;[timezone|offset]] , eg DTIBZ2 or DTIR;America/Denver

And there are a bunch of other conversion codes, with equally complicated parameters.

My end goal is to be able to convert Universe's string data into the appropriate Python object and back again, and in order to do that, I need to understand these conversion codes.

If it helps, I do not need to validate these conversion codes. Once they are set in the database, they are validated there.

Answer 1

I recommend that you use the readnamedfields/writenamedfields methods, this will return OCONV data, and when you write back it handles the ICONV.

import u2py help( u2py.File.readnamedfields) Help on function readnamedfields in module u2py:

readnamedfields(self, *args) F.readnamedfields(recordid, fieldnnames, [lockflag]) -> new DynArray object -- read the specified fields by name of a record in the file

fieldnames is a u2py.DynArray object with each of its fields being a name defined in the dictionary file
lockflag is either 0 (default), or [LOCK_EXCLUSIVE or LOCK_SHARED] [ + LOCK_WAIT]

note: if fieldnames contains names that are not defined in the dictionary, these names are replaced by @ID and no exception is raised