如何在值中添加缺少的字符

def add_missing_chars(value, length, fillchar=' '):
    return value.ljust(length, fillchar)

# 示例
value = "123"
result = add_missing_chars(value, 5, '0')
print(result)  # 输出: "00123"

function addMissingChars(value, length, fillChar = ' ') {
    return value.padStart(length, fillChar);
}

// 示例
let value = "123";
let result = addMissingChars(value, 5, '0');
console.log(result);  // 输出: "00123"

public class StringUtil {
    public static String addMissingChars(String value, int length, char fillChar) {
        return String.format("%" + length + "s", value).replace(' ', fillChar);
    }

    public static void main(String[] args) {
        String value = "123";
        String result = addMissingChars(value, 5, '0');
        System.out.println(result);  // 输出: "00123"
    }
}