How can I find, increment and replace in php?

Question

I have strings in the form \\d+_\\d+ and I want to add 1 to the second number. Since my explanation is so very clear, let me give you a few examples:

Answer 1

Use explode (step-by-step):

$string = "123456_2";

echo $string;

$parts = explode("_", $string);

$lastpart = (int)$parts[1];

$lastpart++;

$newstring = $parts[0] . "_" . (string)$lastpart;

echo $newstring;

This separates the string on the "_" character and converts the second part to an integer. After incrementing the integer, the string is recreated.