How to delete the same elements in php array

In PHP development, array is a frequently used data type. When processing data in an array, there may be duplicate elements in the array, in which case the array needs to be deduplicated. PHP provides a variety of methods to achieve array deduplication. This article will introduce one of the methods - deleting identical elements.

1. Use the array_unique function to implement array deduplication

PHP provides a built-in function array_unique to implement array deduplication. Its syntax is as follows:

array array_unique ( array $array [, int $sort_flags = SORT_STRING ] )

The parameter description of this function is as follows:

$array: Array to remove duplicates.

$sort_flags: Sorting flags, optional. The default is SORT_STRING (sort by string). Optional values ​​include:

SORT_REGULAR - Sort values ​​according to PHP's rules.
SORT_NUMERIC - Sort values ​​according to their size.
SORT_STRING - Sort values ​​according to the order of strings.

This function returns a new array after deduplication.

2. Deleting the same elements implementation steps

Deleting the same elements in the array can be divided into the following steps:

1) Define a new array $new_array , and define a variable $i to record several different elements that already exist in the new array.

2) Traverse the original array $old_array and compare the elements with the elements in the new array $new_array each time. If the element already exists in the new array, it means that the element is repeated and skipped directly; if the element does not exist in the new array, it means that the element is different. Add the element to $new_array and change the value of $i plus 1.

3) Return the new array $new_array.

3. Delete the same element implementation code example

The following is a code example using the method of deleting the same element:

/ /Original array
$old_arr = array(1,2,2,3,4,5,5,5,6);

//Define new array and count variable
$new_arr = array();
$i = 0;

//Traverse the old array
foreach($old_arr as $val){

if(in_array($val, $new_arr)){
    //如果存在，跳过
    continue;
}else{
    //否则添加到新数组中，并且$i+1
    $new_arr[$i] = $val;
    $i++;
}

}

/ /Output new array
print_r($new_arr);
?>

After executing the code, the output result is:

Array
(

[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6

)

It can be seen that the method of deleting the same elements successfully removes the duplicate elements in the array and retains the different elements.

4. Summary

The built-in array_unique function in PHP can easily implement array deduplication operations. However, if you need to delete the same elements, you can also use the above method, whose effect is similar to the array_unique function. No matter which method is used, it can help us better handle the data in the array.

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