Question

今天我自己用JavaScript写了我的第一个程序（耶！）。这是一个乐透号码选择器，从1到49之间随机选择我的六个彩票号码。虽然它似乎工作正常，没有重复，我希望程序以数字顺序打印数字到警报框。任何帮助，将不胜感激。我的代码如下：

var firstNumber = Math.round(Math.random() * 49);
var secondNumber = Math.round(Math.random() * 49);
var thirdNumber = Math.round(Math.random() * 49);
var fourthNumber = Math.round(Math.random() * 49);
var fifthNumber = Math.round(Math.random() * 49);
var sixthNumber = Math.round(Math.random() * 49); 


 if(firstNumber === secondNumber || firstNumber === thirdNumber || 
    firstNumber === fourthNumber || firstNumber === fifthNumber ||           
    firstNumber === sixthNumber || firstNumber === 0) {
      Math.round(Math.random() * 49);
 } else if(secondNumber === firstNumber || secondNumber === thirdNumber || 
           secondNumber === fourthNumber || secondNumber === fifthNumber || 
           secondNumber === sixthNumber || secondNumber === 0) {
      Math.round(Math.random() * 49);
} else if (thirdNumber === firstNumber || thirdNumber === secondNumber || 
           thirdNumber === fourthNumber || thirdNumber === fifthNumber || 
           thirdNumber === sixthNumber || thirdNumber === 0) {
      Math.round(Math.random() * 49);
} else if (fourthNumber === firstNumber || fourthNumber === secondNumber || 
           fourthNumber === thirdNumber || fourthNumber === fifthNumber || 
           fourthNumber === sixthNumber || fourthNumber === 0) {
      Math.round(Math.random() * 49);
} else if(fifthNumber === firstNumber || fifthNumber === secondNumber || 
          fifthNumber === thirdNumber || fifthNumber === fourthNumber || 
          fifthNumber === sixthNumber || fifthNumber === 0){
      Math.round(Math.random() * 49);
} else if(sixthNumber === firstNumber || sixthNumber === secondNumber || 
          sixthNumber === thirdNumber || sixthNumber === fourthNumber || 
          sixthNumber === fifthNumber || sixthNumber === 0) {
      Math.round(Math.random() * 49);
} else {
      alert(firstNumber + ", " + secondNumber + ", " + thirdNumber + ", " + 
      fourthNumber + ", " + fifthNumber + ", " + sixthNumber);
}

Answer 1

如果你使用数组，生成和改组会更容易。数组有一个内置方法sort，可以对它们的项进行排序。不幸的是，这些项目按照它们的文本表示进行排序，所以5在41之后。为了解决这个问题，你可以指定你自己的比较两个项目的比较回调函数。该比较在内部用于对整个数组进行排序。有关该流程的文档可以在on the Mozilla Developer Network找到。

＆＃13;

var numbers = [];
for (var i = 0; i < 6; i++){
  numbers.push(Math.round(Math.random() * 49));
}

numbers.sort(
   function(a, b) {
     return a - b;
   });

alert(numbers);

＆＃13;

但是，此代码（如您自己的代码）可以生成重复项。一个更好的解决方案是采用数字1到49的数组，对该数组进行洗牌，然后从该数组中选择前5个数字。

生成一个数字为1到49的数组可以简单地使用上面代码片段中的for循环来完成，只有你可以将i推送到数组而不是生成数字。

改组阵列有点困难，特别是做得对。幸运的是，关于该主题有this other question，它有很多很好的答案和很好的改组算法。

Answer 2

可能有一种更有效的方法来处理这个问题。试试吧：

＆＃13;

@Before("@annotation(authorized) && execution(* *())") // no string
public void authorize(JoinPoint joinPoint, Authorized authorized) {
  helper(joinPoint,authorized,null);
}

// 1 argument, which is the string
@Before("@annotation(authorized) && execution(* *(..)) && args(str)") 
public void authorize(JoinPoint joinPoint, Authorized authorized, String str) {
  helper(joinPoint,authorized,str);
}

＆＃13;

Answer 3

很简单。

 var text =""
    for (i=1;i<=7;i++) {
       noppa = Math.round((Math.random() * 38) + 1);
       text = text + " " + noppa;
    }

JavaScript乐透号码选择器 - 需要数字顺序的结果

3 个答案: