Python正则表达式-匹配多次

Question

I am wanting to match a character a specific number of times. For example, I am wanting to match an author's name in a HTML string that looks like this:

base>"author's name"</span>

The following regex matches any character in between "base>" and "/span>" and returns only the author's name:

base>\s*(.*?)(?=\s*<\/span>)

However, the HTML file contains 50 instances of this and the above regex returns all 50 matches. How would I modify it so that only the first 10 instances of the matches are returned?

Answer 1

It is possible to make a regex that captures the first ten instances of that regex by concatenating it after itself delimited by .*? . You can then use the first ten capture groups to extract the authors:

base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>).*?base>\\s*(.*?)(?=\\s*<\\/span>)

This is however not what you usually want to do as it makes it relatively hard to change the number of authors you search for. Finding all captures and using only the first few might be more CPU intensive but will make it easier to respond to changing requirements.