python - Use argparse to parse a list of objects -
i have program function takes class initializer , list of objects. each object consists of 3 variables id, value, , tag.
class package(): def __init__(self, id, value, name): if (value <= 0): raise valueerror("amount must greater 0") self.id = id self.value = value self.tag = tag class purchase(): def submit(some_list): //do stuff def main(): //help here! parser = argparse.argumentparser() parser.add_argument("id", help="id") parser.add_argument("value", help="value") parser.add_argument("tag", help="tag") args = parser.parse_args() some_list = [args.id, args.value, args.tag] submit(some_list) i'm trying implement argparse in main() can run program doing like: python foo.py "int0 [(int1, float1, int2), (int3, float2, int4) ....]". number of objects in list variable , depends on user input.
initializer = num0 //first package object package.id = num1 package.value = num2 package.tag = num3 //second package object package.id = num4 package.value = num5 package.tag = num6
you can make custom argument type , use ast.literal_eval() parse value.
working sample:
import argparse ast import literal_eval class package(): def __init__(self, id, value, tag): if (value <= 0): raise valueerror("amount must greater 0") self.id = id self.value = value self.tag = tag def packages(s): try: data = literal_eval(s) except: # todo: avoid bare except , handle more specific errors raise argparse.argumenttypeerror("invalid 'packages' format.") return [package(*item) item in data] parser = argparse.argumentparser() parser.add_argument('--packages', dest="packages", type=packages, nargs=1) args = parser.parse_args() print(args.packages) now if run script, list of package class instances printed:
$ python test.py --packages="[(1, 1.02, 3), (40, 2.32, 11)]" [[<__main__.package instance @ 0x10a20d368>, <__main__.package instance @ 0x10a20d4d0>]] 
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