好像您只想获取不带参数的url部分。可以像这样简单地实现。

url = "https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593"
real_url = url.split('?')[0]

//real_url = https://www.bilibili.com/video/av52135588

您已经说过需要为此使用函数，并且需要了解原理。 Bilibili网站就像一个youtube。那里有很多视频。您必须进行编程才能从您输入的任何视频网址中获取真实网址。我将展示如何做到这一点。

def  getUrlFromBilibili(url):
    real_url = url[:url.find('?')]
    return real_url;

URL = input("Copy and Paste your Bilibili url = ")
#https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593
print("Real url is = ",getUrlFromBilibili(URL))

输出-：

Copy and Paste your Bilibili url = https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593

Real url is = https://www.bilibili.com/video/av52135588

现在我将解释这段代码

#Start of the function

def  getUrlFromBilibili(url):      #This the function which we use to store our url
    real_url = url[:url.find('?')] #In here we remove all characters after '?' in your url including '?'
    return real_url;               #After that we return our shorten url 

#End of the function


URL = input("Copy and Paste your Bilibili url")  #In here You can Enter any video url from Bilibili.com

print("Real url is = ",getUrlFromBilibili(URL))         #After all actions shorten url is displaying in here.

重要

如果您只想从该网址获取真实网址-> https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593您可以使用此代码

def  getUrlFromBilibili(url):
    real_url = url[:url.find('?')]
    return real_url;

print("Real url is = ",getUrlFromBilibili("https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593"))

输出-：

Copy and Paste your Bilibili url = https://www.bilibili.com/video/av52135588?from=search&seid=5625791913889140593

Real url is = https://www.bilibili.com/video/av52135588