Checks if a string ends with a number in php

Question

I want to do a test of variable that starts with a string that I know; and it ends with a number that I don't know, so the test that I did is:

foreach ($json as $key => $value) {
    if ($key == 'IF-MIB::ifDescr.'."$[0-9]")
        echo $key . '=>' . $value . '<br/>';
}

I tested with this, but it doesn't work.

Answer 1

Like this:

$str = 'IF-MIB::ifDescr1';

 if(preg_match('/^IF-MIB::ifDescr([0-9]+)$/', $str, $match)){
      echo $match[1];
 }

Outputs:

 1

Live Demo

So putting it all together for your use case:

foreach ($json as $key => $value) {
   if (preg_match('/^IF-MIB::ifDescr[0-9]+$/', $key)){
       echo $key . '=>' . $value . '<br/>';
   }
}

The ^ at the starts denotes that the string must start with I, and the extra brackets and plus this time state that after the IF-MIB::ifDescr, there can be any number of numbers.

Just to explain:

• ^ is Start of string
• IF-MIB::ifDescr match literal string
• [0-9] character set 0 through 9, + one or more times "greedy"
• $ end of string

And in the first one

• (...) capture group, which is used to return what is matched inside it.

So $match[1] is what is captured by the first capture group, $match[0] is the full match.