Python中如何捕获不在非捕获组内的目标模式？

Hey there! Let's figure out how to capture those target tokens while skipping the common contractions you want to avoid.

You already have a regex to match the contractions you don't want ('ll, 've, 't), and now you need the opposite: grab tokens like 'v and 'w that aren't part of those excluded contractions. The trick here is using a negative lookahead to rule out the unwanted patterns before matching what you do want.

Here's the working code example:

import re
x = "I'll be going home I've the 'v ' isn't want I want to split but I want to catch tokens like 'v and 'w ' ."
# Breakdown of the regex pattern:
# (?i) = case-insensitive matching (so 'V' or 'W' would also be caught)
# ' = matches the single quote
# (?!ve|ll|t) = negative lookahead: ensures the characters after ' aren't "ve", "ll", or "t"
# \w = matches a single alphanumeric character (perfect for your 'v/'w use case)
pattern = r"(?i)'(?!ve|ll|t)\w"
matches = re.findall(pattern, x)
print(matches)  # Output: ["'v", "'v", "'w"]

Let me break down the regex piece by piece to make it clear:

• (?i): Turns on case-insensitive matching, so you don't have to worry about uppercase vs lowercase letters.
• ': Literally matches the single quote at the start of your target tokens.
• (?!ve|ll|t): This is the key part—it checks that the characters immediately after the single quote are NOT "ve", "ll", or "t". This skips exactly the contractions you want to avoid.
• \w: Matches a single letter (or number, though your use case is letters) to capture the token you care about. If you ever need to capture longer tokens (like 'xyz), just change this to \w+.

If you want to make sure you're only capturing standalone tokens (not part of a longer word), you can add a word boundary at the end: (?i)'(?!ve|ll|t)\w\b. This prevents matches like 'v from 'vw (though that scenario doesn't come up in your sample text).

内容的提问来源于stack exchange，提问作者alvas