How to determine whether there are the same values ​​in an array in php

In PHP, we can use some functions to determine whether the same value exists in the array. This article will introduce several methods to determine whether the same value exists in an array.

Method 1: Use the in_array() function

In PHP, we can use the in_array() function to determine whether a value exists in the array. This function returns true if an array contains the same value.

The following is a sample code that uses the in_array() function to determine whether the same value exists in the array:

$array = array("apple", "banana", "orange", "apple");
if (in_array("apple", $array)) {
    echo "Array contains apple";
} else {
    echo "Array does not contain apple";
}

In the above example, we first define an array containing the same value, and then use The in_array() function determines whether the array contains the value "apple". If the array contains the value "apple", output "Array contains apple", otherwise output "Array does not contain apple".

Method 2: Use the array_count_values() function

Use the array_count_values() function to count the number of occurrences of each value in an array. If identical values ​​exist in an array, the function returns an associative array containing the identical values ​​and their number of occurrences.

The following is a sample code that uses the array_count_values() function to determine whether the same value exists in an array:

$array = array("apple", "banana", "orange", "apple");
$count = array_count_values($array);
if (max($count) > 1) {
    echo "Array contains duplicate values";
} else {
    echo "Array does not contain duplicate values";
}

In the above example, we first define an array containing the same value, and then use The array_count_values() function counts the number of occurrences of each value in the array. If the maximum value is greater than 1, it means that the same value exists in the array, and "Array contains duplicate values" is output. Otherwise, "Array does not contain duplicate values" is output.

Method 3: Use the array_unique() function and count() function

We can also use the array_unique() function to remove duplicate values ​​in the array, and use the count() function to count the length of the array. If the same value exists in an array, the length of the array after deduplication is different from the length of the original array.

The following is a sample code that uses the array_unique() function and count() function to determine whether the same value exists in the array:

$array = array("apple", "banana", "orange", "apple");
$unique = array_unique($array);
if (count($array) == count($unique)) {
    echo "Array does not contain duplicate values";
} else {
    echo "Array contains duplicate values";
}

In the above example, we first define an array containing the same value array, then use the array_unique() function to remove duplicate values ​​in the array, and use the count() function to count the length of the array. If the length after deduplication is the same as the length of the original array, it means that the same value does not exist in the array, and "Array does not contain duplicate values" is output. Otherwise, "Array contains duplicate values" is output.

Through the introduction of the above three methods, we can choose the appropriate method according to our needs to determine whether the same value exists in an array.

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