Python:optparse是否可以具有ACTION属性以像STORE和STORE_TRUE一样起作用? [英] Python: Can optparse have the ACTION attribute to act both like STORE and STORE_TRUE?

问题描述

我正在使用optparse来获取命令行输入.

I am using optparse to get command line input.

让我们说我正在运行脚本demo.py，它会创建一些输出.但是除非我指定命令行输入，否则输出不会写入文件.

Lets say that I am running a script demo.py and it creates some output. But unless I specify the command line input, the output is not written to a file.

我正在尝试执行以下操作:

I am trying to do the following:

python demo.py应该运行脚本，但不要将输出写入任何地方.

python demo.py in command line should run the script, but not write the output anywhere.

python demo.py -o应该将输出写入我的默认文件名output.txt.

python demo.py -o in command line should write the output to my default file name output.txt.

python demo.py -o demooutput.txt应该将输出写入文件demooutput.txt.

python demo.py -o demooutput.txt in command line should write the output to file demooutput.txt.

PS:我不希望从optparse切换到argparse.

PS: I would not prefer to switch to argparse from optparse.

推荐答案

您可以使用选择解析回调来实现这一目标.

You can use optparse-callbacks to achieve this.

这是在您的用例中起作用的方式.

Here is how it wiill work for your use case.

parser.add_option("-o", action="callback", dest="output", callback=my_callback)

def my_callback(option, opt, value, parser):
     if len(parser.rargs) > 0:
         next_arg = parser.rargs[0]
         if not next_arg.startswith("-"):
             # Next argument is not another option
             del parser.rargs[0]
             setattr(parser.values, option.dest, next_arg)
             return
     # If not processed, set the default value
     setattr(parser.values, option.dest, "output.txt")

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