How to remove duplicate items from a set of numbers in php

PHP is a popular programming language, and one of the common operations is to process numbers. In PHP, sometimes we need to find duplicates in a set of numbers and remove them. Here's how to remove duplicates from a set of numbers using PHP.

1. Using the array_unique function

PHP provides an array_unique function that can help us easily remove duplicates from an array. This function accepts an array as argument and returns a new array containing only the distinct values ​​from the original array.

The following is a sample code using the array_unique function:

$numbers = array(1, 2, 3, 3, 4, 5, 5);
$unique_numbers = array_unique($numbers);
print_r($unique_numbers);

Output result:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
    [5] => 5
)

In the above code, the array $numbers contains some repeated numbers. Using the array_unique function, we can get a new array $unique_numbers that contains only one occurrence of the number.

2. Using loops and in_array functions

In addition to using the array_unique function, we can also use loops and in_array functions to handle repeated numbers.

The following is a sample code using a loop and in_array function:

$numbers = array(1, 2, 3, 3, 4, 5, 5);
$unique_numbers = array();

foreach ($numbers as $number) {
    if (!in_array($number, $unique_numbers)) {
        $unique_numbers[] = $number;
    }
}

print_r($unique_numbers);

Output result:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
    [5] => 5
)

In the above code, we have used a foreach loop to iterate through the array of numbers $numbers. For each number, we use the in_array function to check if that number already appears in our $unique_numbers array. If it doesn't appear, we add the number to the $unique_numbers array.

3. Using the array_flip and array_keys functions

Another way to remove duplicates in an array in PHP is to use the array_flip and array_keys functions.

The following is a sample code using array_flip and array_keys functions:

$numbers = array(1, 2, 3, 3, 4, 5, 5);
$unique_numbers = array_flip(array_keys(array_flip($numbers)));

print_r($unique_numbers);

Output result:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
    [5] => 5
)

In the above code, we first use the array_flip function to convert the number array $numbers Flip the keys and values ​​in the array, then use the array_keys function to get the keys of the new array, which will remove duplicates. Finally, we use the array_flip function again to flip the keys and values ​​so that we get a new array containing only unique values.

Summary

Finding and removing duplicates in an array of numbers can be easily found using any of the above methods. These tips will be very useful if you need to process numbers in PHP.

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