I have a nodejs script that reads in a file and counts word frequencies. I currently feed each line into a function:

function getWords(line) {
    return line.match(/\b\w+\b/g);
}

This matches almost everything, except it misses contractions

getWords("I'm") -> {"I", "m"}

However, I cannot just include apostrophes, as I would want matched apostrophes to be word boundaries:

getWords("hey'there'") -> {"hey", "there"}

Is there a way capture contractions while still treating other apostrophes as word boundaries?

I have a nodejs script that reads in a file and counts word frequencies. I currently feed each line into a function:

function getWords(line) {
    return line.match(/\b\w+\b/g);
}

This matches almost everything, except it misses contractions

getWords("I'm") -> {"I", "m"}

However, I cannot just include apostrophes, as I would want matched apostrophes to be word boundaries:

getWords("hey'there'") -> {"hey", "there"}

Is there a way capture contractions while still treating other apostrophes as word boundaries?

• javascript
• regex
• node.js
• cpu-word

• How can you tell that I'm should be split but hey'there' should not? Sounds like this might require a dictionary? – Aaron Dufour Commented Dec 31, 2014 at 3:31
• will "hey'there'" really appear like that, or will it have a space like "hey 'there'"? – Wesley Smith Commented Dec 31, 2014 at 3:38
• 3 What if the input is "I'm Steve O'Conner's 'friend'"? How would you know that O'Conner's is actually one word, not three? Or what if the matched apostrophes you mention contain a contraction with another apostrophe? – nnnnnn Commented Dec 31, 2014 at 3:39
• @nnnnnn my answer below seems to cover that case but it could use more testing – Wesley Smith Commented Dec 31, 2014 at 3:46
• 1 My question is, for the record, neither a joke nor rhetorical. You're going to have a hard time getting the answer you want unless you provide actual criteria for making the determination. @DelightedD0D's answer is good, but it drops the apostrophe from words like "'twas" and "'ow", which are also contractions, and it's not clear whether that's important to you. – Aaron Dufour Commented Dec 31, 2014 at 4:15

2 Answers 2

The closest I believe you could get with regex would be line.match(/(?!'.*')\b[\w']+\b/g) but be aware that if there is no space between a word and a ', it will get treated as a contraction.

As Aaron Dufour mentioned, there would be no way for the regex by itself to know that I'm is a contraction but hey'there isn't.

See below:

You can match letters and a possible apostrophe followed by letters.

line.match(/[A-Za-z]+('[A-Za-z]+)?/g