How to remove empty array elements in php

Two removal methods: 1. Use the array_filter() function to filter the array and delete null elements, the syntax is "array_filter($arr)". 2. Use the foreach statement to loop through the associative array, use empty() in the loop body to determine the null element, and use the unset() function to delete the element based on the key name. The syntax is "foreach($arr as $k=>$v) {if(empty($v)){unset($arr[$k]);}}".

The operating environment of this tutorial: windows7 system, PHP8.1 version, DELL G3 computer

Method 1: Use The array_filter() function filters the array and deletes elements with empty values

The array_filter() function, also known as the callback function, is used to filter the elements of the array using a user-defined function. It iterates over each value in the array, passing them to a user-defined function or callback function.

When the array_filter() function is used to declare a callback function, it will delete false values ​​(null values), but if the callback function is not specified, all elements in the array with a value equal to FALSE, such as null, will be deleted String or NULL value.

Implementation code

function f($arr){
	$newarr = array_filter($arr); 
	echo "过滤后的数组：";
	var_dump($newarr);
}

Call f($arr) function

$arr = array(11,'',null,12,false,0); 
var_dump($arr);
f($arr);

Method 2: foreach statement empty() function unset() function

• Use the foreach statement to loop through the array

• In the loop body, use empty() to determine whether the array elements are empty one by one, and use the unset() function to delete empty values ​​based on the key name

Implementation code:

<?php
header("Content-type:text/html;charset=utf-8");
function f($arr){
	foreach ($arr as $k=>$v){
	    if(empty($v)){
			unset($arr[$k]);  
		}
	}

	echo "过滤后的数组：";
	var_dump($arr);
}


$arr = array(11,&#39;1&#39;,&#39;&#39;,&#39; &#39;,&#39;0&#39;,&#39;0.0&#39;,0.0,null,12,false,0); 
var_dump($arr);
f($arr);
?>

Function description:

empty() The function is used to check whether a variable is empty.

empty() Determines whether a variable is considered empty. When a variable does not exist, or its value is equal to FALSE, then it is considered not to exist. empty() does not generate a warning if the variable does not exist.

The following values ​​will be considered empty by empty():

• "" (empty string)

• 0 (0 as an integer)

• 0.0 (0 as a floating point number)

• "0" (0 as a string)

• NULL

• FALSE

• ##array() (an empty array)

• $var; (a variable declared but without a value)

unset() The function is used to destroy the given variable.

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