如何使用argparse将列表作为命令行参数传递?

  • 问题:
  • 我试图将列表作为参数传递给命令行程序。有没有argparse将列表作为选项传递的选项?在

    parser.add_argument('-l', '--list',
    type=list, action='store',
    dest='list',
    help='<Required> Set flag',
    required=True)

    脚本的名称如下所示

    python test.py -l "265340 268738 270774 270817"

  • 答案:
  • TL;DR

    使用nargs选项或action选项的“append”设置(取决于您希望用户界面的行为方式)

    nargs

    parser.add_argument('-l','--list', nargs='+', help='<Required> Set flag', required=True)
    # Use like:
    # python arg.py -l 1234 2345 3456 4567

    nargs='+'接受1个或多个参数,nargs='*'接受零个或更多个参数

    追加

    parser.add_argument('-l','--list', action='append', help='<Required> Set flag', required=True)
    # Use like:
    # python arg.py -l 1234 -l 2345 -l 3456 -l 4567

    使用append可以多次提供选项来构建列表

    不要使用type=list!!!-可能不存在将type=listargparse一起使用的情况。永远

    让我们更详细地看一看人们可能尝试的一些不同方法,以及最终结果

    import argparse

    parser = argparse.ArgumentParser()

    # By default it will fail with multiple arguments.
    parser.add_argument('--default')

    # Telling the type to be a list will also fail for multiple arguments,
    # but give incorrect results for a single argument.
    parser.add_argument('--list-type', type=list)

    # This will allow you to provide multiple arguments, but you will get
    # a list of lists which is not desired.
    parser.add_argument('--list-type-nargs', type=list, nargs='+')

    # This is the correct way to handle accepting multiple arguments.
    # '+' == 1 or more.
    # '*' == 0 or more.
    # '?' == 0 or 1.
    # An int is an explicit number of arguments to accept.
    parser.add_argument('--nargs', nargs='+')

    # To make the input integers
    parser.add_argument('--nargs-int-type', nargs='+', type=int)

    # An alternate way to accept multiple inputs, but you must
    # provide the flag once per input. Of course, you can use
    # type=int here if you want.
    parser.add_argument('--append-action', action='append')

    # To show the results of the given option to screen.
    for _, value in parser.parse_args()._get_kwargs():
    if value is not None:
    print(value)

    以下是您可以预期的输出:

    $ python arg.py --default 1234 2345 3456 4567
    ...
    arg.py: error: unrecognized arguments: 2345 3456 4567

    $ python arg.py --list-type 1234 2345 3456 4567
    ...
    arg.py: error: unrecognized arguments: 2345 3456 4567

    $ # Quotes won't help here...
    $ python arg.py --list-type "1234 2345 3456 4567"
    ['1', '2', '3', '4', ' ', '2', '3', '4', '5', ' ', '3', '4', '5', '6', ' ', '4', '5', '6', '7']

    $ python arg.py --list-type-nargs 1234 2345 3456 4567
    [['1', '2', '3', '4'], ['2', '3', '4', '5'], ['3', '4', '5', '6'], ['4', '5', '6', '7']]

    $ python arg.py --nargs 1234 2345 3456 4567
    ['1234', '2345', '3456', '4567']

    $ python arg.py --nargs-int-type 1234 2345 3456 4567
    [1234, 2345, 3456, 4567]

    $ # Negative numbers are handled perfectly fine out of the box.
    $ python arg.py --nargs-int-type -1234 2345 -3456 4567
    [-1234, 2345, -3456, 4567]

    $ python arg.py --append-action 1234 --append-action 2345 --append-action 3456 --append-action 4567
    ['1234', '2345', '3456', '4567']

    外卖:

    1:我不是说一般。。我的意思是使用引号将列表传递给argparse不是您想要的。在