如何从字符串中获取数字？

import re

def extract_numbers_from_string(string):
    numbers = re.findall(r'\d+', string)
    return [int(num) for num in numbers]

string = "abc123def456"
numbers = extract_numbers_from_string(string)
print(numbers)  # 输出：[123, 456]

function extractNumbersFromString(string) {
    let numbers = "";
    for (let i = 0; i < string.length; i++) {
        if (!isNaN(parseInt(string[i]))) {
            numbers += string[i];
        }
    }
    return parseInt(numbers);
}

let string = "abc123def456";
let number = extractNumbersFromString(string);
console.log(number);  // 输出：123456

public class Main {
    public static void main(String[] args) {
        String string = "abc123def456";
        int number = Integer.parseInt(string.replaceAll("[^0-9]", ""));
        System.out.println(number);  // 输出：123456
    }
}