How to generate random array using PHP

PHP is a very popular programming language and its built-in functions and libraries make it very easy to process data and generate random numbers and arrays. In this article, we will discuss how to generate a random array using PHP.

Generate random numbers

In PHP, PHP’s built-in functions rand() and mt_rand() can be used to generate random numbers. The following are instructions for their use:

1. rand() Function

rand() The function can be used in a given Generate a random number between the two numbers, as shown below:

$number = rand(0,10); // 生成一个介于0和10之间的随机数

The 0 and 10 here are the boundaries of the range and can be adjusted as needed. One drawback of this function is that the random numbers it generates are not "truly random" because the way it is implemented is by "randomizing" the generation using turning the computer clock cycle on or off.

2. mt_rand() function

mt_rand() function is rand() function Improved version, its use is more widespread and recommended. It uses more advanced mathematical algorithms to generate random numbers. The usage method is as follows:

$number = mt_rand(0,10); // 生成一个介于0和10之间的随机数

is the same as the rand() function, where 0 and 10 are the range boundaries for generating random numbers .

Generate a random array

Generating a random array is more complicated than generating random numbers because you need to consider how to generate multiple random numbers and store them into an array. Here are several ways to generate random arrays:

1. Use for loop statements

Use for loop statements are the most The basic method of generating a random array is to loop and generate random numbers a specified number of times, and add each random number to the array. The code is as follows:

$array = array(); // 声明一个空数组

for($i=0; $i<10; $i++){ // 迭代10次生成10个随机数，并添加到数组中
    $array[] = mt_rand(0,10); // 生成随机数，并添加到数组中
}

In the above code, the array array is initially empty, and the mt_rand() function is used to generate random numbers in each loop, and Add them to the array.

2. Using array_fill() Function

array_fill() The function can be used to generate a specified number of identical values array, it is more concise and efficient than the for loop statement. The code is as follows:

$array = array_fill(0, 10, mt_rand(0,10)); // 生成一个包含10个随机数的数组

In the above code, the array array contains 10 random numbers, and the range of each random number is between 0-10 between.

3. Using array_map() Function

array_map() The function can be used on each element of the array. Typically, it executes a callback function for each element in the array, operating on the array element from a list of multiple array arguments provided in an optional second argument. However, here we can take advantage of this feature to generate random arrays. An example is as follows:

$array = array_map(function(){ return mt_rand(0,10); }, array_fill(0, 10, null)); // 生成一个包含10个随机数的数组

In the above code, an anonymous function is used to generate random numbers and applied to each element of the array generated by the "array_fill()" function.

Summary

In this article, we introduced three ways to generate random arrays using PHP: using the for loop statement, using array_fill() function, and use the array_map() function. These methods are feasible and effective. By using these methods you can easily generate random arrays of any length and range. However, please note that due to the nature of random numbers, different algorithms and implementations may have certain biases in generating random numbers. So please pay attention to choosing a good random number generation algorithm when generating random arrays.

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