How to move specified array cells in PHP

In PHP, array is a very useful data type that can be used to save a set of values ​​and can be manipulated to meet different needs. When dealing with arrays, sometimes we need to move elements in the array to achieve better data allocation and use. This article will introduce how to move specified array cells in PHP.

1. Use the array_splice() function to move the specified unit

array_splice() is a very practical function provided by PHP. It is used to remove a specified number of elements from an array and replace it with new elements. Replace them. In addition to removing elements, array_splice() can also be used to move the position of elements in an array.

The usage of the array_splice() function is as follows:

array_splice(array &$input, int $offset, int $length = count($input), mixed $replacement = [])

Parameter description:

$input: the array to be operated on.

$offset: The array index of the element to be moved.

$length: Indicates the number of array elements that need to be moved. The default is from $offset to the end of the array.

$replacement: Array of new elements used to replace moved elements.

Code example:

// 演示数组
$arr = ['a', 'b', 'c', 'd', 'e'];

// 将数组下标为3的元素向前移动一位
array_splice($arr, 2, 1, [$arr[3]]);

// 输出移动后的新数组
print_r($arr);

Run the above code, the output result is as follows:

Array
(
    [0] => a
    [1] => b
    [2] => d
    [3] => c
    [4] => e
)

2. Use array_shift() and array_push() to move the specified unit

Another way to move specific array elements is to use the array_shift() and array_push() functions. The array_shift() function is used to remove the first element of the array and return the value of the element, which can be used to move the element position of the array. The array_push() function is used to add new elements to the end of the array. We can use these two functions together to move the element at a specified position to the end of the array.

Code example:

// 演示数组
$arr = ['a', 'b', 'c', 'd', 'e'];

// 移动数组下标为2的元素到末尾
array_push($arr, array_shift(array_splice($arr, 2, 1)));

// 输出移动后的新数组
print_r($arr);

In the above code, we first use the array_splice() function to remove the element with index 2 from the array and return it. Then use the array_shift() function to remove the returned element, and then use the array_push() function to add it to the end of the array. The final new array is the moved array.

3. Use the array_replace() function to move the specified unit

In addition to the array_splice() function, array_shift(), and array_push() functions, there is also a method that can move the specified unit-array_replace(() )function. The array_replace() function is used to replace elements in one array with elements in another array, and can also be used to move specified array cells.

Code example:

// 演示数组
$arr = ['a', 'b', 'c', 'd', 'e'];

// 移动数组下标为2的元素到末尾
array_replace($arr, array_slice($arr, 0, 2), array_slice($arr, 3));

// 输出移动后的新数组
print_r($arr);

In the above code, we use the array_slice() function to extract elements with subscripts 0 to 1 and 3 to 4 from the original array, and use array_replace( ) function replaces it with the corresponding position in the original array. Through this method, we can move the element located at the second position (subscript 2) in the original array to the end of the array, achieving the effect of moving the specified unit.

Conclusion

In PHP, moving elements in an array is a very common operation. This article introduces three common methods, including using the array_splice() function, using the array_shift() and array_push() functions, and using the array_replace() function. These methods have different applicability in different practical application scenarios, and we can choose according to the specific situation.

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