文本文件中的Argparse自定义帮助 [英] Argparse custom help from text file

问题描述

由于它的灵活性，我想使用argparse库，但是我无法禁用默认的帮助对话框以显示来自文本文件的自定义对话框.我要做的就是在传递"-h"或"--help"选项时显示文本文件中的文本.这是我如何尝试的示例:

I want to use the argparse library because of its flexibility, but I am having trouble disabling the default help dialogue to show a custom one from a text file. All I want to do is display the text from the text file when the "-h" or "--help" option is passed. Here is an example of how I am trying this:

parser = argparse.ArgumentParser(add_help=False)
parser.add_argument("file", type=str, nargs='+')
parser.add_argument("-xmin", type=float)
parser.add_argument("-xmax", type=float)
parser.add_argument("-ymin", type=float)
parser.add_argument("-ymax", type=float)
parser.add_argument("-h", "--help", action="store_true")

args = parser.parse_args()

if args.help is True:
    print isip_get_help()
    exit(-1)

但是它仍然输出:

nedc_[1]: python isip_plot_det.py -h
usage: isip_plot_det.py [-xmin XMIN] [-xmax XMAX] [-ymin YMIN] [-ymax YMAX]
                        [-h]
                        file [file ...]
isip_plot_det.py: error: too few arguments

有什么想法吗?

推荐答案

您得到的是错误消息，而不是帮助(即不是您的-h生成的).

What you are getting is an error message, not the help (i.e. it's not produced by your -h).

isip_plot_det.py: error: too few arguments

错误消息显示了常规帮助的用法部分.您可以使用usage参数进行更改:

The error message shows the usage part of the normal help. You can change that with a usage parameter:

parser = ArgumentParser(usage = 'my custom usage line')

您还可以使用来测试使用情况显示

You can also test the usage display with

parser.print_usage()

或

astr = parser.format_usage()

获取可打印的字符串.

普通的help参数使用特殊的help动作类.其call方法是:

The normal help argument uses a special help action class. Its call method is:

def __call__(self, parser, namespace, values, option_string=None):
    parser.print_help()
    parser.exit()

注意，它将显示parser.print_help()的帮助，然后退出.一旦解析-h字符串，就会发生这种情况.这样，它不会产生任何too few arguments或unrecognized arguments(在解析结束时产生)之类的错误.

Notice that it displays the help with parser.print_help(), and then exits. That occurs as soon as it parses the -h string. That way it doesn't produce any errors like the too few arguments or unrecognized arguments (which are produced at the end of parsing).

因此，定制帮助的另一种方法是将ArgumentParser子类化，并定义您自己的print_help方法.您还可以自定义exit和error方法.

So another way of customizing the help is to subclass ArgumentParser, and define your own print_help method. You can also customize the exit and error methods.

默认print_help是:

def print_help(self, file=None):
    if file is None:
        file = sys.stdout
    self._print_message(self.format_help(), file)

您可以改为自定义format_help.

 class MyParser(argparse.ArgumentParser):
     def format_help(self):
         return 'my custom help message\n   second line\n\n'

样品用量:

In [104]: parser=MyParser(usage='custom usage')
In [105]: parser.parse_args(['-h'])
my custom help message
   second line
   ...

In [106]: parser.parse_args(['unknown'])
usage: custom usage
ipython3: error: unrecognized arguments: unknown
...

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