How to remove all characters from a string, except the integers?

[matheus]

On Thursday, 3 March 2022 at 12:14:13 UTC, BoQsc wrote:
> I've looked around and it seems using regex is the only closest 
> solution.

I'm a simple man who uses D with the old C mentality:

import std.stdio;

void main(){
     string s, str = "4A0B1de!2C9~6";
     foreach(i;str){
         if(i < '0' || i > '9'){ continue; }
         s ~= i;
     }
     writeln("Result: ", s);
}

Result: 401296

Matheus.