How to determine if a value is in an array in php

PHP is one of the most commonly used web development languages. It provides a large number of built-in functions and features, which is extremely convenient for web developers to develop. In PHP, it is sometimes necessary to determine whether a value exists in an array. This is also one of the problems that PHP developers often encounter. This article will introduce how to use PHP to determine whether a value is in an array.

First, we need to understand two very commonly used functions in PHP: in_array() and array_search(). Both functions can determine whether a value exists in the array. Among them, the in_array() function is used to check whether a value exists in the array, and the return value is true or false. The function is used as follows:

$target = 'blue';
$array = array('red', 'green', 'blue', 'yellow');

if (in_array($target, $array)) {
    echo 'Found';
} else {
    echo 'Not found';
}

In the above code, we define an array $array and determine whether the variable $target exists in the array. Because the value of the $target variable is 'blue' and exists in the array $array, the output result of the above code is: Found.

Next, let’s take a look at the second function in PHP: array_search(). This function can also be used to check whether a value exists in an array, and can return the subscript of the value in the array. The function is used as follows:

$target = 'blue';
$array = array('red', 'green', 'blue', 'yellow');

if (($key = array_search($target, $array)) !== false) {
    echo 'Found in array element with index: ' . $key;
} else {
    echo 'Not found in array.';
}

In the above code, we determine whether the variable $target exists in the array $array and obtain its subscript in the array. Because the value of the $target variable is 'blue' and exists in the array $array, the output of the above code is: Found in array element with index: 2.

It should be noted that when using the above two functions to determine whether a value exists in an array, the type must be distinguished (strict mode). In some cases, strong type judgment is very important, otherwise it may cause some unpredictable errors.

The above is the basic method to use PHP to determine whether a value is in an array. Whether it is in_array() or array_search(), they are very common techniques in PHP development. I hope this article will be helpful to you.

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