Learn how to remove blank or duplicate elements from PHP arrays

In our previous article, we learned about the method of splitting a one-dimensional array and dividing the one-dimensional array into a two-dimensional array containing a specified number of elements. If you are interested, you can click on the link to read → "PHP Array Learning Convert a one-dimensional array into a two-dimensional array containing the specified number of elements》. This time we will study and practice PHP arrays and talk about how to remove emptiness and duplication in arrays.

→Related recommendations: 《PHP array learning series summary (continuously updated~)》

The main content of today’s article is to delete the array empty elements and repeated elements.

First let’s take a lookHow to delete empty elements in an array? Here I will introduce two methods.

Method 1, foreach loop empty() unset()

Implementation idea:

• Use foreach statement To traverse the array $array, assign the key name to $key in each loop, and assign the key value to $value
  

foreach($array as $key => $value){  
}

• in the loop , use the empty() function to determine whether $value is empty. If it is empty, use unset() to delete the element

Below we give the complete implementation code:

<?php 
header("content-type:text/html;charset=utf-8");
$array = array("php", 11, &#39;&#39;, 12, "PHP中文网", &#39;&#39;,2021,"mysql"); 
var_dump($array);       
 
// 使用array_filter()函数从数组中移除空元素
$filtered_array = array_filter($array); 
echo "删除空元素后的数组";
var_dump($filtered_array); 
?>

Output result:

Description: In PHP, the empty() function is used to check whether a variable is considered empty.

empty() will consider the variable to be empty when it is equal to the following value:

• ""(empty string)

• 0 (0 as an integer)

• 0.0 (0 as a floating point number)

• ##“0 ”(0 as string)

• NULL

• FALSE

• Array()( An empty array)

• $var (one is declared, but there is no variable with value)

Method 2. Use The array_filter() function performs filtering

If the callback function is omitted, null values ​​will be filtered by default. (array_filter() function will not change the original array)

<?php 
header("content-type:text/html;charset=utf-8");
$array = array("php", 11, &#39;&#39;, 12, "PHP中文网", &#39;&#39;,2021,"mysql",""); 
var_dump($array);       
 
// 使用array_filter()函数从数组中移除空元素
$filtered_array = array_filter($array); 
echo "删除空元素后的数组";
var_dump($filtered_array); 
?>

array_values() function.

var_dump(array_values($filtered_array));

how to remove duplicate array elements.

array_unique() function. If there are two or more values ​​in the array that are the same, the array_unique() function only retains the first value and the other values ​​are removed.

<?php 
header("content-type:text/html;charset=utf-8");
$array = array("php", 11, &#39;&#39;, 11, "PHP中文网",&#39;&#39;,"green",2021,"mysql","","green"); 
var_dump($array);       
 
$result = array_unique($array);
echo "删除重复元素后的数组";
//var_dump(array_values($filtered_array)); 
var_dump($result);
?>

var_dump(array_values($result));

PHP Array Learning: How to Change Key Names" The positions of key and value are interchanged》). Key code:

array_flip(array_flip($array))

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PHP function array array function video explanation, come and learn!

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