How to remove duplicate values ​​from php array?

You can use the array_unique() function in PHP to remove duplicate values ​​from an array; if two or more array values ​​are the same, the array_unique() function will only retain the first element, and the other element values ​​will be Delete; syntax format "array_unique(array)".

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array_unique() Definition and Usage

array_unique() function removes duplicate values ​​from an array and returns the resulting array.

When the values ​​of several array elements are equal, only the first element is retained and the other elements are deleted.

The key names in the returned array remain unchanged.

Syntax

array_unique(array)

Parameters

• array Required. Specifies the input array.

Description

• array_unique() sorts the values ​​as strings first, then keeps only the first encountered key for each value name, and then ignore any subsequent key names. This does not mean that the first occurrence of the same value in an unsorted array will be preserved.

Return value: Returns the filtered array. The returned array will retain the key type of the first array element.

Example 1:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"red");
$a2=array("1"=>"Cat","2"=>"Dog","3"=>"Cat","4"=>"rabbit");
var_dump(array_unique($a1));
var_dump(array_unique($a2));
?>

Output:

array (size=2)
  'a' => string 'red' (length=3)
  'b' => string 'green' (length=5)
array (size=3)
  1 => string 'Cat' (length=3)
  2 => string 'Dog' (length=3)
  4 => string 'rabbit' (length=6)

Example 2:

<?php
$result1 = array("a" => "green", "red", "b" => "green", "blue", "red");
var_dump($result1);
$result2 = array_unique($result1);
var_dump($result2);
?>

Output:

array (size=5)
  'a' => string 'green' (length=5)
  0 => string 'red' (length=3)
  'b' => string 'green' (length=5)
  1 => string 'blue' (length=4)
  2 => string 'red' (length=3)
array (size=3)
  'a' => string 'green' (length=5)
  0 => string 'red' (length=3)
  1 => string 'blue' (length=4)

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