PHP正则表达式模式[关闭]

Question

I'm trying to get the unique ID from a string using PHP regex but I'm having problems generating the regex pattern.

sample urls

lesson-computer-networking-xpt2-t9295779.html // need to get 9295779
lesson-summary-t9295778.html //need to get 9295778
lesson-part2-t94.html //need to get 94

The length of first portion of the string depends on the page title but last portion is always -txxxxxxxx.html

Can someone help me to generate the pattern?

Answer 1

You could use the below regex to get the number after t which was before .html,

-t\K\d+(?=\.html)

OR

(?<=-t).*(?=\.html)

DEMO

Your PHP code would be,

<?php
$data = <<<'EOT'
lesson-computer-networking-xpt2-t9295779.html
lesson-summary-t9295778.html
lesson-part2-t94.html
EOT;
$regex = '~(?<=-t).*(?=\.html)~';
preg_match_all($regex, $data, $matches);
var_dump($matches);
?>

Output:

array(1) {
  [0]=>
  array(3) {
    [0]=>
    string(7) "9295779"
    [1]=>
    string(7) "9295778"
    [2]=>
    string(2) "94"
  }
}

Explanation:

• (?<=-t) A lookbehind is used to look after specific pattern. In our case the regex engine should set the matching marker just after to the string -t.
• .*(?=\.html) Next it matches all the characters upto the string .html(ie, when .html is seen by the regx engine, it suddenly stops the matching)