regex preg_match for digit in middle for a string

Question

ddw_0_op1
ddw_1_op1
ddw_2_op1
ddw_3_op1
ddw_4_op1

in these strings of array how i can extract or preg_match only the number in middle that increase . t

Answer 1

use the preg_match function:

$str = "ddw_01_fdfd";
preg_match('/.+_([0-9]+)_.+/', $str, $matches);
echo $matches[1];

Output:

01

Another way to do it is by explode the string by _:

$xpl = explode('_', $str);
$middleStr = $xpl[1];

The explode function splits a string by string, in that case create an array made by all substring contained in $str dividing them by _.

Try it here.