How to insert array into php

In PHP programming, arrays are a very common data structure, and it is often necessary to add, delete, modify, and check arrays. Inserting data is one of the commonly used operations in development. This article will introduce the array insertion method in PHP in detail.

1. PHP array insertion method

In PHP, you can use array_push(), [], array_splice() and other methods to add new data to the array. They are introduced separately below.

1. array_push() method

array_push() method can directly add one or more elements to the end of the array, and its return value is the number of elements in the array after adding the elements. Number:

$colors = array("red","green");
array_push($colors,"blue","yellow");
print_r($colors);

The output result is:

Array
(
    [0] => red
    [1] => green
    [2] => blue
    [3] => yellow
)

2. Square brackets "[]" method

Use square brackets "[]" to directly add elements The method is simple and easy to use, suitable for situations where the order or index value of the newly added element is known:

$colors = array("red","green");
$colors[] = "blue";
print_r($colors);

The output result is:

Array
(
    [0] => red
    [1] => green
    [2] => blue
)

3. array_splice() method

The array_splice() method is a multifunctional function that can not only insert new elements into the array, but also delete array elements, and even sort the array.

The following is the syntax for inserting new elements into an array:

array_splice(array,start,length,insert array/item);

Among them, array is the original array, start is the position to be inserted, length is the number of elements to be deleted, and insert is the number of elements to be deleted. The inserted array or element.

For example, insert a new element "c" into an alphabetical array:

$letters = array("a", "b", "d", "e");
array_splice($letters, 2, 0, "c");
print_r($letters);

The output result is:

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

2. Application scenarios of PHP array insertion

1. Insert new data into the array

In actual development, it is necessary to continuously insert new data into the array, such as inserting new users into the array that stores user information information. In this case, you can use array_push(), [], array_splice() and other methods to operate.

2. Insert new data in the middle position

Sometimes it may be necessary to insert new data in the middle position of the array, such as when inserting a new element into a sorted array, This can be done using the array_splice() method.

3. Dynamic generation of arrays

In PHP development, sometimes it is necessary to dynamically generate an array to store data. In this case, array_push(), [] and other methods can be used to operate .

3. Notes

1. When using array_push() and [] methods, if the array is empty, the value inserted using [] will become the key is an element of 0.
2. For insertion using the array_splice() method, if the number of elements to be deleted is not specified, no elements will be deleted, but new elements will only be inserted at the specified position.
3. Before inserting a new element into the array, it is best to determine whether the element already exists to avoid errors caused by repeated insertion.

4. Summary

This article introduces three methods of array insertion in PHP: array_push(), [], array_splice(), and lists the needs in actual development Things to note. In development, which method to choose for operation needs to be chosen according to the scenario and needs to achieve the best results.

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