Summarize the method of deleting array elements by value in php

PHP is a high-level programming language that has many powerful features, one of which is to delete elements from an array by value. In the process of programming, we often need to delete elements in the array in order to make full use of the server's resources. In this article, we will introduce ways to delete elements by value in PHP.

First, let’s take a look at the functions that have been built into PHP to delete array elements. PHP provides many functions to delete array elements, such as unset(), array_splice(), array_shift(), and array_pop(). These functions can delete array elements based on key or index. However, if you want to remove elements by value, you need to use another function. Here are several ways to delete array elements by value:

Method 1: Use the array_search() and unset() functions

The array_search() function can search for a given value in the array, and returns its key. Then, use the unset() function to remove the element from the array. Here is an example:

$array = array("apple", "banana", "cherry", "apple");
$key = array_search("banana", $array); //从数组中搜索"banana"，返回键
unset($array[$key]); //从数组中删除键对应的元素

The above code will delete the element with the value "banana" in the array.

Method 2: Use the array_filter() function

The array_filter() function will return a new array that only contains the elements passed the test. You can use this function to create a new array that does not contain the elements you want to delete. Here is an example:

$array = array("apple", "banana", "cherry", "apple");
$new_array = array_filter($array, function($value) {
  return $value != "banana"; //返回新数组中不包含"banana"的元素
});

The above code will create a new array that does not contain elements with the value "banana".

Method 3: Use the array_diff() function

The array_diff() function will return the difference between the two arrays. You can use this function to create a new array containing elements from the original array that do not contain the element you want to delete. Here is an example:

$array = array("apple", "banana", "cherry", "apple");
$delete = array("banana"); //要删除的元素
$new_array = array_diff($array, $delete); //返回不包含"banana"的原始数组元素的新数组

The above code will create a new array that does not contain elements with the value "banana".

When using these methods, you need to pay attention to some details. For example, if there are multiple elements with the same value in the array, the above method will remove all these elements. If you only want to remove the first element with that value, you can specify a starting position when using array_search().

Summary

PHP provides a variety of methods to delete array elements. Deleting elements by key or index is very simple, you can use the unset(), array_splice(), array_shift() or array_pop() functions. Removing elements by value requires the use of other functions, such as the array_search(), array_filter(), or array_diff() functions. Before using these methods, you need to pay attention to whether there are multiple elements with the same value in the array.

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