I derive some settings from my parser that I latter store on disk to be reloaded again, during the reload I want to overwrite some values but keep the first ones, similar to new default values. I want to have a priority of args2 > args1 > default values, however I face the challenge on how to determine the highest priority, especially when I pass the default value explicitly in arg2, it should not fall back to args1, i.e. a simple comparison with the default is not sufficient. args1 = ["-a", "1", "--bar", "2"] # Run 1 args2 = ["--bar", "default-bar", "-c", "3"] # Run 2, override bar with default args2_b = ["-c", "3"] # Run 2b, bar should be restored from Run 1 # Equivalent full args for Run 2 wanted = ["-a", "1", "--bar", "default-bar", "-c", "3"] wanted_b = ["-a", "1", "--bar", "2", "-c", "3"] from argparse import ArgumentParser parser = ArgumentParser() # required arguments without defaults can be present too parser.add_argument("--foo", "-a", default="default-foo") parser.add_argument("--bar", "-b", default="default-bar") parser.add_argument("--baz", "-c", default="default-baz") results1 = parser.parse_args(args1) print(results1) # Namespace(foo='1', bar='2', baz='default-baz') results2 = parser.parse_args(args1) print(results2) # Namespace(foo='default-foo', bar='default-bar', baz='2') # merge results # ...? I do not want to make things too complicated and hard to maintain, therefore manually looking at sys.argv does not look feasible (I have many arguments, shorthand codes, usage of dest, ...). I use tap Typed Argument Parser - if that info helps to find a better solution, also I would like to keep most of tap's features, i.e. to define most arguments in a class and keep meaningful default values there. TL;DR: how could I differentiate between these two cases in Run 2? # Run 1 file.py -a 1 --bar 2 # Run 2, that references some state from Run 1 # Use passed value: file.py -c 3 --restore-run 1 --bar "default-bar" # Use value from Run 1 file.py -c 3 --restore-run 1 Related questions: python get changed (non-default) cli arguments? - helpful and closest to my problem, but fails with the restored default value Python command line arguments check if default or given - problem and solution are far off Python argparse: default value or specified value - asks for const Continue reading...
