regex to truncate long words and append ellipses

Question

This question has effective solutions for identifying long words: Regex to parse long words

How would I then truncate them at a set value and append "..."

Basically, I want to apply a preg_replace on a long string and truncate any very long words (not truncate the entire string -- just the long words).

The regex flavor should be PHP.

Answer 1

edit: This works for me

$pattern = "/(?<=(\s\w{10}))(\w*\s)/";

This pattern effectively matches any word characters characters followed by a space, that were preceded by a space and 10 word characters.

Then just call something like this:

preg_replace($pattern,"... ",$string);

Hope that helps :)

edited: Actually should use \s instead of space, this will match any whitespace characters.

Answer 2

I guess this regular expression does the trick. I tested using php 5.3.6 and worked fine.

$pattern = "/(\\b\\w{10})\\w+\\b/";
echo preg_replace($pattern, "$1...", "pequeno palavramedia palavrabemgrandemesmo\n");

Where is {10} you should replace by the maximum allowed size without replacement. If you want a maximum word size of N, you should use {N-3}, because of the length of the dots.

It should run fine for big strings, because it describe a regular language and the running time should be O(n). Of course, it depends on the implementation of regex.