Php匹配单词代码不能在php 5.1.6上运行

Question

i have piece of code that works fine on my local test server but on live server for some reason it does not. Php version on live server is 5.1.6.

$subject = 'random words to check';   
$terms = explode(' ', 'word1 word2 check');
$wordIndex = array_flip(preg_split('/\P{L}+/u', mb_strtolower($subject), -1, PREG_SPLIT_NO_EMPTY));
foreach ($terms as $term) {
    if (isset($wordIndex[$term])) {
        echo "match>".$term;
    }
}

Answer 1

First employ some basic debugging to discover what's happening on each system

• dump the output of mb_strtolower
• dump the output of preg_split
• dump the output of array_flip