Argparse example of color conversion in SE 2019-05-18

colors.py

#!/usr/bin/env python

def hex2rgb(color):
    color = color.lstrip("#")
    return tuple(
        int(color[idx:idx+2], 16)
        for idx in (0, 2, 4)
    )


def rgb2hex(color):
     return "#{0:02x}{1:02x}{2:02x}".format(*color)


if __name__ == '__main__':

    import argparse

    parser = argparse.ArgumentParser(
        description = "awesome color parser of awesomeness",
        epilog = "if any problems talk to Michael definitely not Ben"
    )

    parser.add_argument(
        "-r", "--rgb", action="store_true", default=False,
        help="convert an rgb value to hex"
    )

    parser.add_argument(
        "-x", "--hex", action="store_true", default=False,
        help="convert hex colors to rgb"
    )

    parser.add_argument(
        "colors", type=str, nargs="+", metavar="color",
        help="pass one or more hex values or 3 RGB values"
    )

    # Get the args from the command line
    args = parser.parse_args()

    if args.rgb:
        if len(args.colors) % 3 != 0:
            parser.error("please provide 3 RGB arguments for each color")

        try:
            colors = [
                int(color) for color in args.colors
            ]
        except ValueError:
            parser.error("RGB requires all int values")

        for idx in range(0, len(colors), 3):
            rgb = colors[idx:idx+3]
            print(rgb2hex(rgb))


    elif args.hex:
        for color in args.colors:
            print(hex2rgb(color))

    else:
        parser.error("specify --rgb or --hex")