How to get the collection of two arrays using different methods in PHP

For PHP developers, they often need to process arrays, and one of the most common operations for processing arrays is to merge two arrays to obtain their collection. This article will introduce how to use different methods to obtain the collection of two arrays in PHP.

Method 1: Use the array_merge function

PHP provides the array_merge function to merge two or more arrays. The following is the sample code:

//声明两个数组
$array1 = array('a', 'b', 'c');
$array2 = array('d', 'e', 'f');

//合并数组
$result = array_merge($array1, $array2);

//输出
print_r($result);

The output result is:

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

We can see that by utilizing the array_merge function, our two arrays were successfully merged without duplicate values.

So what if there are duplicate values? How will the array_merge function handle it? Let us continue to look at the following demonstration:

//声明两个数组
$array1 = array('a', 'b', 'c');
$array2 = array('b', 'c', 'd');

//合并数组
$result = array_merge($array1, $array2);

//输出
print_r($result);

The output is:

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

We can see that in the first array and the second array there are values ​​of 'b' and The elements of 'c' are repeatedly output in the merged array.

Method 2: Use the array_unique function

If you want to obtain the "unique after merging" element set of two arrays, then we can use the array_unique function. The following is the sample code:

//声明两个数组
$array1 = array('a', 'b', 'c');
$array2 = array('b', 'c', 'd');

//合并数组并去重
$result = array_unique(array_merge($array1, $array2));

//输出
print_r($result);

The output result is:

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

We can see that through the array_unique function, we successfully obtained the combined unique element set of the two arrays.

Method 3: Use the " " operator

In addition to the array_merge function and array_unique function, we can also use the " " operator to obtain the collection of two arrays. The following is a sample code:

//声明两个数组
$array1 = array('a', 'b', 'c');
$array2 = array('b', 'c', 'd');

//获取数组合集
$result = $array1 + $array2;

//输出
print_r($result);

The output result is:

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

We can see that when using the " " operator, we also successfully obtain the collection of two arrays.

Summary

In PHP, there are many ways to obtain the collection of two arrays, and the above three methods are the most commonly used. Different methods are suitable for different scenarios, and developers can choose the method that suits them best according to the specific situation.

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