Regex - Match all numbers until character

Question

Lets assume I have a string like this

1234hello567u8 915 kl15

I want to match all the numbers up until the first space (So, 12345678)

I know I can use this: [^\s]* to match everything until the first space.. But how

How do i use [^\s]* to only match numbers?

Answer 1

In PHP you can use this:

$re = '/\h.*|\D+/'; 
$str = "1234hello567u8 915 kl15"; 

$result = preg_replace($re, '', $str);
//=> 12345678 

RegEx Demo

Answer 2

Regex is about matching a pattern but it seems like you don't know exactly pattern of your text.

I suggest you like this

1. Replace all [a-z] to "", by using

   regex: "s/[a-z]//g"

   output: "12345678 915 15"

2. Capture text you want,

   regex: "(^\d+)"

   output: "12345678"