如何检查字符串的内容是否为数值？

import re

def is_number(s):
    pattern = re.compile(r'^[-+]?\d+$')
    return bool(pattern.match(s))

s = '123'
print(is_number(s))  # True

s = '12.3'
print(is_number(s))  # False

function isNumber(s) {
    return /^[-+]?\d+$/.test(s);
}

let s = '123';
console.log(isNumber(s));  // true

s = '12.3';
console.log(isNumber(s));  // false

public static boolean isNumber(String s) {
    if (s == null || s.length() == 0) {
        return false;
    }
    try {
        Double.parseDouble(s);
        return true;
    } catch (NumberFormatException e) {
        return false;
    }
}

String s = "123";
System.out.println(isNumber(s));  // true

s = "12.3";
System.out.println(isNumber(s));  // true