How to output variable in textfield?

What I’m trying to do is a textfield, for max players for multiplayer game. How can I make it so he can only write numbers, and so the output in textfield goes to a variable? I’m stuck on this, anyone with a better idea on how to do this is very appreciated. Thanks in advance.

Alright tried this, it works - I wrote it as an Editor, but the idea is applicable in GUI code too… The key elements are: 1- the regular expression. 2- the int.TryParse function to turn the string into an int.

using System.Text.RegularExpressions;
using UnityEditor;
using UnityEngine;

public class TestEditor : Editor
	string strValue = "";
	int intValue;
	Regex numbers = new Regex(@"^\s*[0-9]*$"); // this means: anything that 'starts' with any number of spaces followed by any number of digits between 0-9. the $ signifies the end, the ^ is the start. you could use \d instead of [0-9]

	public override void OnInspectorGUI()
			string newValue = GUILayout.TextField(strValue);
			if (numbers.IsMatch(newValue)) {
				strValue = newValue;
				int.TryParse(strValue, out intValue);