如何编辑列表中的字符串/网址？

Question

I've scraped and created a list of URLs and am trying to replace a section of each url in the list.

Each URL contains the section '/season/1288' that I'm trying to remove. 'productions' is my list of urls, and this is the code I was using:

prod_lists = [str.replace('/season/1288', '') for i in productions]
print(prod_lists)

It returns the error

TypeError: replace expected at least 2 arguments, got 1

Answer 1

To make a list using list comprehension in your code, you should use the variable i, not str .

productions = [
    '/season/1288/aaa',
    '/season/1288/bbb',
    '/season/1288/ccc',
]
prod_lists = [i.replace('/season/1288', '') for i in productions]
print(prod_lists)

This will print:

['/aaa', '/bbb', '/ccc']

The reason you received the error msg is because you called replace function using str class, not str instance. It automatically passes a str instance as a first parameter, known as self but, in this code replace cannot find a str instance to pass as a first parameter because str is a class, not an instance.

Interestingly, if you run a following code, explicitly passing str instance '/season/1288/ccc', you can see the result replaced by 1 without an error msg.

productions = ['/season/1288/aaa']
prod_lists = [str.replace('/season/1288/ccc', '/season/1288', '1') for i in productions]
print(prod_lists) # This prints: ['1/aaa']