How to write the winning number in javascript

Preface

In front-end development, it is often necessary to generate some random numbers, such as the winning number in a lottery. Javascript provides a method to generate random numbers, which can easily generate winning numbers. This article will introduce in detail how to generate winning numbers in Javascript.

The basic principle of generating winning numbers

The generation of winning numbers needs to consider randomness and deduplication. First, we need a way to generate random numbers. Javascript provides the Math.random() method, which can generate a random number between 0 and 1.

Next, we need to generate a set of winning numbers. The winning numbers need to meet the following two conditions:

1. Each winning number is a unique value.

2. Each winning number has an equal probability of appearing in the number pool.

In order to satisfy the above two conditions, you can use an array to store all the numbers in the number pool, use the random sorting method of the array to shuffle the order of each number, and then take out the winning numbers in order from the beginning.

Implementation method

Let’s implement a simple lottery program. Suppose we have a number pool that contains 100 numbers (00001~00100), and we need to draw 10 numbers from it as the winning numbers.

1. Generate a number pool

We can use a for loop and the push method of an array to generate a number pool.

var codePool = [];   //号码池

for(var i=1;i<=100;i++){

  var code = i<10?'000'+i:i<100?'00'+i:'0'+i;   //格式化号码

  codePool.push(code);

}

In the above code, we use the ternary operator and string concatenation to format the number into a 5-digit string. For example, the number 1 is converted into the string "00001", and the number 11 is converted into the string "00011".

2. Disrupt the number pool

We use the sort method of the array to disrupt the order of numbers in the number pool. The sort method needs to pass in a random sorting function. For example, Math.random() can be used to generate the sorting basis.

codePool.sort(function(){return Math.random()-0.5});

3. Draw the winning numbers

Next, we traverse the number pool from scratch and take out the first 10 numbers as the winning numbers.

var winCodes = [];    //中奖号码

for(var i=0;i<10;i++){

  winCodes.push(codePool[i]);

}

4. Display the winning numbers

Finally, we will display the generated winning numbers.

console.log(winCodes);

Complete code

The final code is as follows:

var codePool = [];   //号码池

//生成号码池

for(var i=1;i<=100;i++){

  var code = i<10?'000'+i:i<100?'00'+i:'0'+i;

  codePool.push(code);

}

//打乱号码池

codePool.sort(function(){return Math.random()-0.5});

//抽取中奖号码

var winCodes = [];

for(var i=0;i<10;i++){

  winCodes.push(codePool[i]);

}

//展示中奖号码

console.log(winCodes);

Summary

This article introduces the basic principles and implementation methods of generating winning numbers in Javascript. Javascript provides the Math.random() method to generate random numbers. Using the random sorting method of the array can disrupt the order of numbers in the number pool, thereby achieving random draws. Finally, we reveal the winning numbers. The method described in this article is a simple implementation, and in practice it can be improved according to specific needs.

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