How to Remove Items from Set based on a Condition in PHP - Step by Step Examples

How to Remove Items from Set based on a Condition in PHP ?

Answer

To remove items from a set (which can be represented using an array) based on a condition in PHP, you can use the array_filter function.

✐ Examples

1 Remove Even Numbers from an Array

In this example,

First, we create an array named $numberArray with values $numberArray = [1, 2, 3, 4, 5];.
Next, we use the array_filter function to filter out the even numbers from the array. This function takes the array and a callback function as arguments.
The callback function checks if a number is odd using the modulus operator %. If the number is odd, the callback function returns true, and the number is kept in the array.
The filtered array is then assigned to the variable $filteredArray.
Finally, we print the filtered array to verify that even numbers have been removed.

PHP Program

<?php
$numberArray = [1, 2, 3, 4, 5];
echo "Original Array: ";
print_r($numberArray);
$filteredArray = array_filter($numberArray, function($number) {
    return $number % 2 !== 0;
});
echo "Array after removing even numbers: ";
print_r($filteredArray);
?>

Output

Original Array: Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
)
Array after removing even numbers: Array
(
    [0] => 1
    [2] => 3
    [4] => 5
)

2 Remove Strings Longer Than 4 Characters from an Array

In this example,

First, we create an array of strings named $stringArray with values $stringArray = ["apple", "banana", "orange", "kiwi"];.
Next, we use the array_filter function to filter out the strings longer than 4 characters from the array. This function takes the array and a callback function as arguments.
The callback function checks if the length of a string is less than or equal to 4 using the strlen function. If the condition is true, the callback function returns true, and the string is kept in the array.
The filtered array is then assigned to the variable $filteredArray.
Finally, we print the filtered array to verify that strings longer than 4 characters have been removed.

PHP Program

<?php
$stringArray = ["apple", "banana", "orange", "kiwi"];
echo "Original Array: ";
print_r($stringArray);
$filteredArray = array_filter($stringArray, function($str) {
    return strlen($str) <= 4;
});
echo "Array after removing strings longer than 4 characters: ";
print_r($filteredArray);
?>

Output

Original Array: Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => kiwi
)
Array after removing strings longer than 4 characters: Array
(
    [3] => kiwi
)

Summary

In this tutorial, we learned How to Remove Items from Set based on a Condition in PHP language with well detailed examples.

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