如何确定 Python 函数接受哪些参数？

Question

运行以下代码：

pdf = pdftotext.PDF(f,layout='raw')

产生了这个错误：

'layout' is an invalid keyword argument for this function

有没有办法列出这个函数和任何函数将采用哪些参数？

Answer 1

help python 中的函数可用于查看 class 或函数的文档。在 python 中编码时，我喜欢保留 IPython 解释器运行。 IPython 专门为此目的提供了 ? 和 ?? 等运算符。

Answer 2

help(f) 显示 python 构造 f 的文档和参数，如 class 或函数。

例如在控制台上

help(print)

显示

Help on built-in function print in module builtins:

print(...)
    print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)

    Prints the values to a stream, or to sys.stdout by default.
    Optional keyword arguments:
    file:  a file-like object (stream); defaults to the current sys.stdout.
    sep:   string inserted between values, default a space.
    end:   string appended after the last value, default a newline.
    flush: whether to forcibly flush the stream.

帮助我的新功能 f ...

def f(): None

显示

Help on function f in module main:

f()

https://docs.python.org/3/library/functions.html#help

Answer 3

使用python的help内置函数。

help([object])

Invoke the built-in help system. (This function is intended for interactive use.) If no argument is given, the interactive help system starts on the interpreter console. If the argument is a string, then the string is looked up as the name of a module, function, class, method, keyword, or documentation topic, and a help page is printed on the console. If the argument is any other kind of object, a help page on the object is generated.

假设您来自 Python 2.7，并且需要有关 Python 的 print 功能的帮助 3. 转到交互式提示并键入 help(print)：

>>> help(print)

   Help on built-in function print in module builtins:

   print(...)
       print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)
   
       Prints the values to a stream, or to sys.stdout by default.
       Optional keyword arguments:
       file:  a file-like object (stream); defaults to the current sys.stdout.
       sep:   string inserted between values, default a space.
       end:   string appended after the last value, default a newline.
       flush: whether to forcibly flush the stream.
   (END)

如您所见，print 有 4 个关键字参数（sep、end、file、flush）。完成后按 q 退出。

如何确定 Python 函数接受哪些参数？

How can I determine which arguments a Python function takes?

python

arguments

function

pdftotext

help([object])