Use the PHP function 'array_search' to find a specified value in an array and return its key name

Use the PHP function "array_search" to find the specified value in the array and return its key name

In PHP development, array is a very common and practical data structure. When we need to find the key name corresponding to a specific value in the array, we can use the "array_search" function provided by PHP.

First, let's look at the basic syntax of the "array_search" function:

mixed array_search ( mixed $needle , array $haystack [, bool $strict = false ] )

This function accepts three parameters:

• $needle: the value to be found .
• $haystack: Array to search.
• $strict: Optional parameter, the default is false, indicating that the value is compared in non-strict mode, that is, only the content of the value is compared without comparing the type. If set to true, it means strict mode is used when comparing values, even types must be compared together.

The following uses a specific example to demonstrate how to use the "array_search" function. Suppose we have an array $fruits that stores some fruits, and now we want to find the key corresponding to "apple".

$fruits = array("banana", "apple", "orange", "grape");

$key = array_search("apple", $fruits);

echo "The key for 'apple' is: " . $key;

The output of the code will be:

The key for 'apple' is: 1

In this example, we first define an array $fruits that contains several fruits. Next, we use the "array_search" function to find the key name corresponding to "apple" and assign the result to the variable $key. Finally, we output the results through the echo statement.

It should be noted that if the searched value has multiple duplicates in the array, the "array_search" function will only return the first matching key name.

Of course, if the search results are required to strictly match the type of the value, we can set the optional $strict parameter to true. The following is an example of using strict mode:

$fruits = array("banana", 1, "2", true);

$key = array_search(1, $fruits, true);

echo "The key for 1 is: " . $key . "
";

$key = array_search("1", $fruits, true);

echo "The key for '1' is: " . $key;

The output will be:

The key for 1 is: 1
The key for '1' is:

In this example, we define an array $fruits, which contains a number 1 and a character String "1". First, we use strict mode to find the key name corresponding to the number 1 and assign the result to the variable $key. Since the types of the number 1 and the string "1" do not match, the "array_search" function does not find the corresponding key name and the result is false.

To summarize, using the PHP function "array_search" can easily find the specified value in the array and return its key name. We just need to pass in the value we want to find and the array we want to search, and the function will return the first matching key name. If you require a strict match on the type of a value, you can set the optional $strict parameter to true. This function is very useful when dealing with some array operations. I hope this article will be helpful to you.

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