How to determine if an element is in an array in php

In PHP, determining whether an element is in an array is a frequently used function. In this article, we will learn how to use PHP functions to detect whether an array contains an element, including the in_array() function and array_search() function in PHP.

1. in_array() function

The in_array() function is used to detect whether a specified value exists in an array. If it exists, it returns true, otherwise it returns false.

The syntax of the in_array() function is as follows:

in_array($value, $array, $strict)

Among them, $value is the element to be found; $array is the array to be searched; $strict is an optional parameter, if set to true , it will check whether the element type is exactly the same as the element type in the array, the default is false.

Sample code:

//定义一个数组
$arr = array("apple", "banana", "orange", "grape");

//查找元素是否存在于数组中
if (in_array("orange", $arr)) {
    echo "元素存在于数组中";
} else {
    echo "元素不存在于数组中";
}

Running results:

元素存在于数组中

2. array_search() function

array_search() function is used to search for specified items in the array value and returns the key name of the first occurrence of the value. If the value is not found, false is returned.

The syntax of the array_search() function is as follows:

array_search($value, $array, $strict)

Among them, $value is the element to be found; $array is the array to be searched; $strict is an optional parameter, if set to true , it will check whether the element type is exactly the same as the element type in the array, the default is false.

Sample code:

//定义一个数组
$arr = array("apple", "banana", "orange", "grape");

//查找元素是否存在于数组中
if (($key = array_search("orange", $arr)) !== false) {
    echo "元素存在于数组中，键名为：" . $key;
} else {
    echo "元素不存在于数组中";
}

Running result:

元素存在于数组中，键名为：2

Note that since the array_search() function searches for values ​​in the array, the key name may be an integer or a string or other types of values.

3. Summary

Both of the above two functions can be used to detect whether an element exists in an array in PHP. If you are simply checking whether an element exists, then using the in_array() function is sufficient. But if you need to find the key name of an element in an array, it is more convenient to use the array_search() function.

In addition to the above two functions, you can also use a foreach loop to traverse the array to detect whether an element exists in the array. However, it is more efficient and convenient to use PHP built-in functions to find elements.

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