How to disrupt the order of an array in php but keep the subscripts unchanged

In PHP programming, we often encounter scenarios where we need to disrupt the order of array elements, such as needing to sort a set of random numbers, or needing to randomly sample a set of data. Generally speaking, we can use the shuffle() function that comes with PHP to shuffle the array elements, but this function will change the key values ​​of the elements, causing the subscripts of the original array order to change, thereby destroying the original data structure. Integrity. This article will introduce a method to implement PHP array shuffling without changing the order of the array subscripts.

Method implementation

In order to implement PHP array shuffling without changing the array order subscript, we can use a method similar to the shuffling algorithm, that is, copy all array elements to a new one array and randomly generate a new sort order. Then iterate over the original array and fill its elements into the new array one by one in the new order. In this way, the subscript order of the original array has not changed, but the sort order of the array elements has been randomized. The PHP code is as follows:

function shuffleArray($arr) {
//Copy array
$newArr = $arr;

//Randomly sort
shuffle($newArr );

// Traverse the original array
foreach ($arr as $key => $value) {

// 将元素按照新顺序填充到新数组中
$arr[$key] = $newArr[$key];

}

// Return the new array
return $arr;
}

This function receives an input array $arr and returns a new array in shuffled order. In the implementation, we first use $newArr = $arr to completely copy the original array into the new array to avoid potential problems caused by references. Next, we use PHP’s own shuffle() function to randomly sort the new array. Finally, we iterate over the original array, fill its elements into the new array one by one in the new order, and return the new array.

Advantages and disadvantages of this method

Using the above method can achieve PHP array shuffling without changing the order of the original array subscripts. It has the following advantages:

1. Using PHP The built-in shuffle() function implementation is concise and easy to understand.
2. By completely copying the original array to the new array, potential problems caused by references can be avoided and the code will be more robust.
3. It has a wide range of applications, without considering the data structure and number of elements of the original array, and is suitable for any type of array.

However, this method also has the following shortcomings:

1. In the implementation, an additional array needs to be used to store the shuffled order, and the array cannot be shuffled in place. .
2. For large arrays, this method is less efficient and requires traversal and filling operations based on extra space. If massive amounts of data need to be scrambled, it is recommended to use more efficient algorithms.
3. For application scenarios that need to ensure absolute randomness (such as password generation), since the bottom layer of the shuffle() function relies on random seed calls, the absolute randomness of the data cannot be guaranteed, and a more secure random generation algorithm needs to be used.

Summary

In PHP programming, disrupting the order of array elements is a common application scenario. Using the shuffle() function is a simple way to shuffle arrays in PHP, but this method will change the order of the original array subscripts, thereby destroying the original array data structure. In order to achieve PHP array shuffling without destroying the subscript order of the original array, we can use a method similar to the shuffling algorithm. This method has certain limitations and cannot disrupt the array in place, but it has a wide range of applications and the code is concise and easy to understand. It is a practical tool algorithm in PHP programming.

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