PHP array_intersect_ukey() function (with example)

Hey everyone,

I'm trying to use the `array_intersect_ukey()` function in PHP, but I'm having some trouble understanding how it works exactly. I've looked at the PHP documentation, but I could really use some examples to help me grasp it better.

From what I understand, `array_intersect_ukey()` compares the keys of two or more arrays and returns the entries that have matching keys. What I'm unsure about is how it uses the user-defined comparison function.

Could someone please provide me with a clear example of how to use `array_intersect_ukey()` and explain how the comparison function works? It would be great if you could also walk me through the steps of how the function is executed in the example.

Any help would be greatly appreciated. Thank you in advance!

All Replies

ymccullough

July 01 2023 at 06:04 AM

Hey there,

I've actually used `array_intersect_ukey()` before, so I can share my experience with you.

In my case, I had two arrays that I needed to compare based on their keys. Let's call them `$array1` and `$array2`. To use `array_intersect_ukey()`, we need to define a user-defined comparison function that determines how the keys should be compared.

Here's an example of how I used `array_intersect_ukey()`:

php
function keyComparator($key1, $key2) {

    // Custom logic for key comparison, e.g., case-insensitive comparison

    

    // For example, let's assume we want case-insensitive comparison

    return strcmp(strtolower($key1), strtolower($key2));

}



$array1 = ["apple" => 1, "banana" => 2, "orange" => 3];

$array2 = ["Apple" => 4, "BANANA" => 5, "grapes" => 6];



$intersectedArray = array_intersect_ukey($array1, $array2, 'keyComparator');

In the above example, I defined the `keyComparator()` function to compare the keys case-insensitively using `strcmp()` and `strtolower()`. This function is passed as the third argument to `array_intersect_ukey()`.

After executing `array_intersect_ukey()`, the `$intersectedArray` will contain the elements from `$array1` whose keys match the keys in `$array2`. However, please note that the comparison is done using our custom `keyComparator()` function.

In this case, the resulting `$intersectedArray` would be:

php
array(2) {

  ["apple"]=>

  int(1)

  ["banana"]=>

  int(2)

}

I hope this example clarifies how `array_intersect_ukey()` works with the user-defined comparison function. If you have any further questions or need more clarification, feel free to ask!

Helpful (10)

fannie25

June 24 2023 at 01:50 AM

Hey folks,

I came across this thread while searching for information on `array_intersect_ukey()` in PHP. I recently had a similar scenario where I needed to compare arrays based on their keys, and I found `array_intersect_ukey()` to be quite useful.

In my case, I had an array called `$originalArray` that contained some data with unique keys. I also had a `$referenceArray` that had some matching and some different keys. My goal was to find the elements in the `$originalArray` that had matching keys in the `$referenceArray`.

To achieve this, I used a callback function called `keyMatcher()` to compare the keys in a customized way:

php
function keyMatcher($key1, $key2) {

    // Custom logic to match only specific keys

    

    // Let's assume we want to match only keys that start with 'prefix_'

    if (strpos($key2, 'prefix_') === 0) {

        return strcmp($key1, $key2);

    } else {

        return -1;

    }

}



$originalArray = ["prefix_key1" => 1, "prefix_key2" => 2, "key3" => 3, "prefix_key4" => 4];

$referenceArray = ["key1" => 5, "prefix_key2" => 6, "prefix_key5" => 7];



$intersectedArray = array_intersect_ukey($originalArray, $referenceArray, 'keyMatcher');

In this example, the `keyMatcher()` function compares the keys and returns 0 if they start with 'prefix_', indicating a match. If the key in `$referenceArray` doesn't start with 'prefix_', I returned -1 to indicate that it should not be considered a match.

When I executed the `array_intersect_ukey()` function, the resulting `$intersectedArray` held the elements from `$originalArray` that had matching keys in `$referenceArray`. In this case, it would contain:

php
array(1) {

  ["prefix_key2"]=>

  int(2)

}

I hope this example helps you understand how to use `array_intersect_ukey()` with a customized comparison function. If you have any further questions or need more examples, feel free to ask. Happy coding!

Helpful (11)

Related Topics

jmcclure

June 17 2023 at 06:05 PM

Hi everyone,

I stumbled upon this discussion while looking for information on `array_intersect_ukey()` in PHP. I recently encountered a situation where this function proved to be quite handy.

In my project, I had two separate arrays, `$array1` and `$array2`, that contained different sets of data. I needed to compare them based on their keys and retrieve the elements with matching keys.

To achieve this, I used a user-defined comparison function called `keyComparator()` that I implemented myself:

php
function keyComparator($key1, $key2) {

    // Custom logic to compare keys

    

    // Let's say we want to compare the lengths of the keys

    return strlen($key1) - strlen($key2);

}



$array1 = ["cat" => 1, "dog" => 2, "elephant" => 3];

$array2 = ["apple" => 4, "banana" => 5, "lion" => 6];



$intersectedArray = array_intersect_ukey($array1, $array2, 'keyComparator');

Here, the `keyComparator()` function compares the lengths of the keys using `strlen()`. If the length of `$key1` is greater than that of `$key2`, it returns a positive value. If `$key1` is shorter, it returns a negative value. If the lengths are equal, it returns zero.

Upon executing `array_intersect_ukey()`, the resulting `$intersectedArray` contains the elements from `$array1` that have matching keys in `$array2`. Based on our custom comparison function, the resulting array would be:

php
array(1) {

  ["dog"]=>

  int(2)

}

I hope this example sheds some light on how `array_intersect_ukey()` works. If you have any further questions or need more examples, feel free to ask. Happy coding!

Helpful (7)

PHP array_intersect_ukey() function (with example)

All Replies

Related Topics

More Topics Related to PHP

More Topics Related to User-defined Comparison Function

Popular Tags

New to LearnPHP.org Community?