How to tell if a PHP array contains a value

In PHP, there are many ways to check whether an array contains a certain value. Below we will introduce them one by one.

1. in_array() function

The in_array() function is a very commonly used function in PHP and can be used to check whether an array contains a certain value. This function accepts two parameters: the value to find and the array to find.

The following is a sample code:

$array = array('apple', 'banana', 'orange');
$check_value = 'banana';
if (in_array($check_value, $array)) {
    echo '该数组中包含' . $check_value;
} else {
    echo '该数组中不包含' . $check_value;
}

Output result:

该数组中包含banana

2. array_search() function

array_search() function too Function in PHP to check if an array contains a value. This function accepts two parameters: the value to find and the array to find.

Different from in_array(), this function returns the key name of the first occurrence of the value to be found in the array. If the value does not exist, returns false.

The following is a sample code:

$array = array('apple', 'banana', 'orange');
$check_value = 'banana';
$array_key = array_search($check_value, $array);
if ($array_key !== false) {
    echo '该数组中包含' . $check_value . ',键名为' .$array_key;
} else {
    echo '该数组中不包含' . $check_value;
}

Output result:

该数组中包含banana,键名为1

3. isset() function

isset() function can Used to check whether a certain key exists in the array. This function accepts one parameter: the key name to be checked.

The following is a sample code:

$array = array('apple', 'banana', 'orange');
$check_key = 0;
if (isset($array[$check_key])) {
    echo '该数组中包含键名为' . $check_key . '的元素';
} else {
    echo '该数组中不包含键名为' . $check_key . '的元素';
}

Output result:

该数组中包含键名为0的元素

4. array_key_exists() function

array_key_exists() function also Can be used to check whether a key exists in an array. This function accepts two parameters: the key name to check and the array to check.

The following is a sample code:

$array = array('apple', 'banana', 'orange');
$check_key = 0;
if (array_key_exists($check_key, $array)) {
    echo '该数组中包含键名为' . $check_key . '的元素';
} else {
    echo '该数组中不包含键名为' . $check_key . '的元素';
}

Output result:

该数组中包含键名为0的元素

To sum up, the above is the method in PHP to determine whether an array contains a certain value. Among them, the in_array() and isset() functions are the most commonly used. We can choose which method to use based on the actual situation.

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