将更多参数传递给这种类型的python函数 [英] Passing more arguments to this type of python function

问题描述

我认为这是非常基本的，但即使是如何向Google提出正确的问题，也似乎无法弄清楚.我正在使用此python websocket客户端建立一些websocket连接.假设我正在使用与该页面相似的代码示例:

I figure this is pretty basic, but can't seem to figure out even how to ask google the right question. I am using this python websocket client to make some websocket connections. Let's just assume I'm using the code example similar to that page:

import websocket
import thread
import time

def on_message(ws, message):
    print(message)

def on_error(ws, error):
    print(error)

def on_close(ws):
    print("### closed ###")

def on_open(ws):
    def run(*args):
        ws.send("Hello")
        time.sleep(1)
        ws.close()
        print("thread terminating...")
    thread.start_new_thread(run, ())


if __name__ == "__main__":
    websocket.enableTrace(True)
    ws = websocket.WebSocketApp("ws://echo.websocket.org/",
                              on_message = on_message,
                              on_error = on_error,
                              on_close = on_close)
    ws.on_open = on_open
    ws.run_forever()

所以我想做的是向on_open函数添加更多参数，如下所示:

So what I am trying to do is add more arguments to the on_open function, something like this:

def on_open(ws, more_arg):
    def run(*args):
        ws.send("Hello %s" % more_arg)
        time.sleep(1)
        ws.close()
        print("thread terminating...")
    thread.start_new_thread(run, ())

但是我不知道如何传递这些参数，所以我尝试了主线程:

But i can't figure out how to pass these arguments in, so I tried in the main thread:

ws.on_open = on_open("this new arg")

但是我得到了错误:

TypeError:on_open()恰好接受2个参数(给定1个参数)

TypeError: on_open() takes exactly 2 arguments (1 given)

我如何将这些新参数传递给我的on_open函数?

How am I going to pass these new arguments to my on_open function?

推荐答案

请记住，您需要分配一个回调.相反，您正在调用一个函数，并将返回值传递给ws，这是不正确的.

Keep in mind that you need to assign a callback. You are instead calling a function and passing the return value to ws, which is incorrect.

您可以使用 functools.partial 来功能更高的一个:

You can use functools.partial to curry a function to a higher order one:

from functools import partial

func = partial(on_open, "this new arg")
ws.on_open = func

当调用func时，它将调用on_open，第一个参数为"this new arg"，然后再传递给func的任何其他参数.在文档链接中查看partial的实现以获取更多详细信息.

When func is invoked, it will invoke on_open with the first argument as "this new arg", followed by any other arguments passed to func. Look at the implementation of partial in the doclink for more details.

这篇关于将更多参数传递给这种类型的python函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！