How to determine whether two arrays are equal in php

In PHP, there are several ways to determine whether two arrays are equal. The following will introduce two common methods:

Method 1: Use == and ===Operator

In PHP, you can use the == and === operators to compare two arrays for equality. The difference between these two operators is as follows:

• == operator indicates equality comparison. If the values ​​of the variables on both sides are equal, the result is true , otherwise the result is false.
• === operator represents a congruent comparison. If the types and values ​​of the variables on both sides are equal, the result is true, otherwise the result is false.

You need to pay attention to a few points when using this method:

• The order of elements in the array will also be compared.
• The comparison of simple values ​​is to compare their values, and the comparison of objects and arrays is to compare their references, which means that they must be the same object or array instance to be considered equal.
• Two arrays are considered equal only if the keys and values ​​in both arrays are the same.

The following is a sample code that uses the == operator to compare whether two arrays are equal:

$arr1 = array(1,2,3);
$arr2 = array(1,3,2);

if ($arr1 == $arr2) {
    echo "两个数组相等";
} else {
    echo "两个数组不相等";
}

Running results:

两个数组不相等

Below This is a sample code that uses the === operator to compare whether two arrays are equal:

$arr1 = array(1,2,3);
$arr2 = array(1,2,3);

if ($arr1 === $arr2) {
    echo "两个数组相等";
} else {
    echo "两个数组不相等";
}

Running result:

两个数组相等

Method 2: Use array_diff() Function

array_diff()The function is used to calculate the difference set of arrays, returning values ​​that exist in the first array but do not exist in other arrays. If two arrays are equal, their difference should be an empty array. Therefore, you can use the array_diff() function to determine whether two arrays are equal.

The specific steps are as follows:

1. Calculate the difference between two arrays.
2. Judge the length of the difference set. If it is 0, then the two arrays are equal, otherwise they are not equal.

The following is a sample code that uses the array_diff() function to compare whether two arrays are equal:

$arr1 = array(1,2,3);
$arr2 = array(1,3,2);

$diff = array_diff($arr1, $arr2);

if (count($diff) == 0) {
    echo "两个数组相等";
} else {
    echo "两个数组不相等";
}

Running result:

两个数组相等

This The advantage of this method is that the order of the elements in the array can be ignored. However, it is important to note that this method may produce incorrect results if the same key-value pair exists in the array. Therefore, in actual use, it is necessary to choose a suitable method to determine whether two arrays are equal according to the specific situation.

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