Ah, I see the issue here! The problem is that the backslash (\) is a special escape character in Python strings. When you write '\' in your list, Python thinks you're trying to escape the closing single quote that follows it. This leaves your string unclosed, which triggers that SyntaxError: EOL while scanning string literal error.

Luckily, there are two simple ways to fix this:

1. Escape the backslash with another backslash #

You can represent a literal backslash by using two backslashes together. Python will interpret '\\' as a single backslash character:

mc = ['^', '$', '[', ']', '{', '}', '-', '?', '*', '+', '(', ')', '|', '\\']

2. Use a raw string #

Prefix the string containing the backslash with an r (for "raw"). Raw strings treat backslashes as literal characters instead of escape sequences, so you don't need to escape it:

mc = ['^', '$', '[', ']', '{', '}', '-', '?', '*', '+', '(', ')', '|', r'\']

Either approach will correctly add the backslash to your list of regex metacharacters without causing a syntax error. Pick whichever you find more readable!

内容的提问来源于stack exchange，提问作者user9062604