使用preg_match_all查找每个单词

Question

I'd like to extract every word seperately from any phrase. I also need to match special characters, such as umlauts.

Currently, I use this:

preg_match_all('/\b([a-zA-ZäöüåÄÖÜÅ]*)\b/', $string, $matches);

However, this gives me redundant and empty matches. For example, "zu spät" returns

Array ( [0] => Array ( [0] => zu [1] => [2] => spät [3] => ) 
        [1] => Array ( [0] => zu [1] => [2] => spät [3] => ) ) 

What is the correct expression to match "any letter"? What can I do about the double and empty matches?

Answer 1

You can try this:

preg_match_all('/\b\p{L}+\b/u', $string, $matches);

Where \p{L} matches any letters.

In your code sample you obtain the result "in double": the first is the whole pattern, the second is the capturing group. This is the reason why I have removed the capture group. To avoid empty results, I have replaced the * quantifier (zero or more times) by the + quantifier (one or more times).