如何將我自己的「幫助」信息添加到Python函數/類？

Question

我知道我可以使用「help（）」來查看包中的現有幫助信息。但是在我編寫自己的函數/類後，如何啓用「幫助」來查看幫助文檔？我知道「評論」的第一行是doc屬性，但這不是我想要的。

我希望自己編譯包，其他人可以從「help（）」中看到。怎麼做？

Answer 1

help()完全基於__doc__屬性（和函數參數的自省），所以請確保您的模塊，您的類和您的函數都有一個文檔字符串。

文檔字符串不一個評論，它是在頂部裸露的字符串字面權：

"""This is a module docstring, shown when you use help() on a module""" 

class Foo: 
    """Help for the class Foo""" 

    def bar(self): 
     """Help for the bar method of Foo classes""" 

def spam(f): 
    """Help for the spam function""" 

例如，流行的第三方requests模塊有一個文檔字符串：

>>> import requests 
>>> requests.__doc__ 
'\nRequests HTTP library\n~~~~~~~~~~~~~~~~~~~~~\n\nRequests is an HTTP library, written in Python, for human beings. Basic GET\nusage:\n\n >>> import requests\n >>> r = requests.get(\'https://www.python.org\')\n >>> r.status_code\n 200\n >>> \'Python is a programming language\' in r.content\n True\n\n... or POST:\n\n >>> payload = dict(key1=\'value1\', key2=\'value2\')\n >>> r = requests.post(\'http://httpbin.org/post\', data=payload)\n >>> print(r.text)\n {\n  ...\n  "form": {\n  "key2": "value2",\n  "key1": "value1"\n  },\n  ...\n }\n\nThe other HTTP methods are supported - see `requests.api`. Full documentation\nis at <http://python-requests.org>.\n\n:copyright: (c) 2016 by Kenneth Reitz.\n:license: Apache 2.0, see LICENSE for more details.\n' 

它由help()直接呈現，連同模塊內容（以及遞歸的內容docstrings）：

>>> help('requests') 
Help on package requests: 

NAME 
    requests 

DESCRIPTION 
    Requests HTTP library 
    ~~~~~~~~~~~~~~~~~~~~~ 

    Requests is an HTTP library, written in Python, for human beings. Basic GET 
    usage: 

     >>> import requests 
     >>> r = requests.get('https://www.python.org') 
     >>> r.status_code 
     200 
[...] 

Answer 2

你可以使用argparse：https://docs.python.org/2/howto/argparse.html。它允許您創建一個可以自定義的--help參數以及添加參數描述。

例子：

parser = argparse.ArgumentParser(description = "Write your help documentation here...") 
parser.add_argument('config.txt', nargs='?', help='Write about your positional arguments here') 
args = parser.parse_args() 

因此，當有人與--help運行您的程序將輸出：

$python yourProgram.py --help 
usage: yourProgram.py [-h] [config.txt] 

Write your help documentation here... 

positional arguments: 
config.txt Write about your positional arguments here 

optional arguments: 
-h, --help show this help message and exit