Use the array_keys() function in PHP to get the key names in the array

Use the array_keys() function in PHP to get the key name in the array

The array_keys() function is a very practical function in PHP, it can return the given All keys in the array.

In PHP, an array is a very commonly used data structure that can store multiple values ​​and access these values ​​through key names. Sometimes, we only need to get the key names in the array without processing the values. In this case, we can use the array_keys() function.

Syntax:
array_keys(array $array, mixed $search_value = null, bool $strict = false): array

Parameters:

##$array : The array to be processed.
• $search_value (optional): The value to search for.
• $strict (optional): Whether to use strict mode for matching.

Return value:

Returns a new array containing all key names in the array.

The following is a specific code example:

<?php
// 示例数组
$fruits = array("apple", "banana", "cherry");

// 获取数组中的键名
$keys = array_keys($fruits);

// 输出结果
foreach ($keys as $key) {
    echo $key . "<br>";
}
?>

In the above code, we define an array named $fruits, which contains three fruit names. Then, we use the array_keys() function to get the key names in the array $fruits and save the result in the $keys variable. Finally, we traverse the $keys array through a foreach loop and output the key names one by one.

Executing the above code will output the following results:

0
1
2

Through the above example, we can see that the array_keys() function returns a new array containing all the key names in the array, and the key names Arrange according to the order in the original array.

It should be noted that the array_keys() function can also accept additional parameters to specify the search value or use strict mode for matching. If the $search_value parameter is specified, only key names matching the value will be returned; if the $strict parameter is specified and set to true, type checking will be performed when matching.

Summary:

The array_keys() function is a very practical function in PHP, which can quickly obtain all the key names in a given array. We can use additional parameters to search for key names or use strict pattern matching as needed. Mastering this function can make you more flexible and efficient when working with arrays.

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