正则表达式问题：如何匹配>与<之间的第三个单词

Got it, let's break this down. Your original regex (?<=&gt;)(\w*)(?=&lt;) works great for grabbing every word wrapped between > and <, but adding {2} directly didn't hit the mark because you weren't accounting for the full surrounding structure of the first two matches. Here's how to fix it:

The Working Regex #

(?:>\w*<){2}>(\w*)<

Let's Break It Down #

• (?:>\w*<){2}: This is a non-capturing group ((?:...)) that matches the full >WORD< structure exactly 2 times. The non-capturing part means we don't save these first two words—we just skip over them.
• >(\w*)<: After skipping the first two matches, this targets the third occurrence. The parentheses around \w* capture the word we actually want.

Example Usage #

If your input string is:

Lorem>First<Ipsum>Second<Dolor>Third<Sit

Running the regex will capture Third as the first (and only) capturing group value.

Why Your Previous Attempts Failed #

• Adding {2} to the lookbehind ((?<=&gt;){2}) would look for two consecutive > characters, which isn't your structure.
• Adding {2} to the lookahead ((?=<){2}) would require two consecutive < characters, which also doesn't match your pattern.
• You need to match the entire >WORD< block for the first two instances before targeting the third.

Alternative (If You Prefer Lookarounds) #

If you specifically want to stick with lookarounds (though the above method is more straightforward), you can use a positive lookbehind that checks for the first two full blocks:

(?<=(?:&gt;\w*&lt;){2}&gt;)(\w*)(?=&lt;)

This works by verifying the word is preceded by two complete >WORD< blocks plus a >, then followed by <.

内容的提问来源于stack exchange，提问作者Fayaz