Arrays are linear data structures used to process data in programming. Sometimes when we are processing arrays we need to add new elements to the existing array. In this article, we will discuss several ways to add elements to the end of an array in PHP, with code examples, output, and time and space complexity analysis for each method.
The following are different ways to add elements to an array:
Use square brackets []
In PHP, the method to add elements to the end of an array is to use square brackets []
. This syntax only works in cases where we want to add only a single element. The following is the syntax:
$array[] = value;
Example
<?php $friends = ['Ayush', 'Antima']; $friends[] = 'Smrita'; // 向末尾添加單個(gè)元素 print_r($friends); ?>
Output
<code>Array ( [0] => Ayush [1] => Antima [2] => Smrita )</code>
Time complexity: O(1)
Space complexity: O(1)
Usage array_push()
array_push()
Function is used to add one or more elements to the end of an array. This method is mainly used when we need to add multiple items at once. The following is the syntax:
array_push($array, $value1, $value2, ...);
Example
<?php $friends = ['Ayush', 'Antima']; array_push($friends, 'Smrita', 'Priti'); // 添加多個(gè)元素 print_r($friends); ?>
The following is the output of the above code:
<code>Array ( [0] => Ayush [1] => Antima [2] => Smrita [3] => Priti )</code>
Time complexity: O(n), if multiple elements are added
Space complexity: O(1)
Usage array_merge()
If you want to combine two arrays, you can use the array_merge()
method to combine multiple arrays into one. This method is useful when we want to add an entire new array of elements to an existing array. The following is the syntax:
$array = array_merge($array1, $array2, ...);
Example
<?php $friends = ['Ayush', 'Antima']; $newFriends = ['Smrita', 'Priti']; $friends = array_merge($friends, $newFriends); print_r($friends); ?>
The following is the output:
<code>Array ( [0] => Ayush [1] => Antima [2] => Smrita [3] => Priti )</code>
Time complexity: O(n)
Space complexity: O(n)
Use the
operator
We can also combine arrays using the
operator. We should always remember that this method mainly applies to associative arrays and preserves the keys of the first array. If the keys overlap, only the value of the first array is preserved. The following is the syntax:
$array = $array1 + $array2;
Example
<?php $group1 = ['Ayush' => 1, 'Antima' => 2]; $group2 = ['Smrita' => 3, 'Priti' => 4]; $friends = $group1 + $group2; print_r($friends); ?>
The following is the output:
<code>Array ( [Ayush] => 1 [Antima] => 2 )</code>
Time complexity: O(n)
Space complexity: O(1)
Usage array_splice()
array_splice()
Function is a very powerful and useful function. This function is used to insert, delete, or replace elements in an array. We can use this method to insert new elements anywhere (including the end). Here is the syntax of this method:
array_splice($array, $offset, $length, $replacement);
Example
<?php $friends = ['Ayush', 'Antima']; array_splice($friends, count($friends), 0, ['Smrita', 'Priti']); // 在末尾插入 print_r($friends); ?>
The following is the output:
<code>Array ( [0] => Ayush [1] => Antima [2] => Smrita [3] => Priti )</code>
Time complexity: O(n)
Space complexity: O(n)
The above is the detailed content of How to Add Elements to the End of an Array in PHP. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

The method to get the current session ID in PHP is to use the session_id() function, but you must call session_start() to successfully obtain it. 1. Call session_start() to start the session; 2. Use session_id() to read the session ID and output a string similar to abc123def456ghi789; 3. If the return is empty, check whether session_start() is missing, whether the user accesses for the first time, or whether the session is destroyed; 4. The session ID can be used for logging, security verification and cross-request communication, but security needs to be paid attention to. Make sure that the session is correctly enabled and the ID can be obtained successfully.

To extract substrings from PHP strings, you can use the substr() function, which is syntax substr(string$string,int$start,?int$length=null), and if the length is not specified, it will be intercepted to the end; when processing multi-byte characters such as Chinese, you should use the mb_substr() function to avoid garbled code; if you need to intercept the string according to a specific separator, you can use exploit() or combine strpos() and substr() to implement it, such as extracting file name extensions or domain names.

UnittestinginPHPinvolvesverifyingindividualcodeunitslikefunctionsormethodstocatchbugsearlyandensurereliablerefactoring.1)SetupPHPUnitviaComposer,createatestdirectory,andconfigureautoloadandphpunit.xml.2)Writetestcasesfollowingthearrange-act-assertpat

In PHP, the most common method is to split the string into an array using the exploit() function. This function divides the string into multiple parts through the specified delimiter and returns an array. The syntax is exploit(separator, string, limit), where separator is the separator, string is the original string, and limit is an optional parameter to control the maximum number of segments. For example $str="apple,banana,orange";$arr=explode(",",$str); The result is ["apple","bana

JavaScript data types are divided into primitive types and reference types. Primitive types include string, number, boolean, null, undefined, and symbol. The values are immutable and copies are copied when assigning values, so they do not affect each other; reference types such as objects, arrays and functions store memory addresses, and variables pointing to the same object will affect each other. Typeof and instanceof can be used to determine types, but pay attention to the historical issues of typeofnull. Understanding these two types of differences can help write more stable and reliable code.

std::chrono is used in C to process time, including obtaining the current time, measuring execution time, operation time point and duration, and formatting analysis time. 1. Use std::chrono::system_clock::now() to obtain the current time, which can be converted into a readable string, but the system clock may not be monotonous; 2. Use std::chrono::steady_clock to measure the execution time to ensure monotony, and convert it into milliseconds, seconds and other units through duration_cast; 3. Time point (time_point) and duration (duration) can be interoperable, but attention should be paid to unit compatibility and clock epoch (epoch)

ToaccessenvironmentvariablesinPHP,usegetenv()orthe$_ENVsuperglobal.1.getenv('VAR_NAME')retrievesaspecificvariable.2.$_ENV['VAR_NAME']accessesvariablesifvariables_orderinphp.iniincludes"E".SetvariablesviaCLIwithVAR=valuephpscript.php,inApach

In PHP, to pass a session variable to another page, the key is to start the session correctly and use the same $_SESSION key name. 1. Before using session variables for each page, it must be called session_start() and placed in the front of the script; 2. Set session variables such as $_SESSION['username']='JohnDoe' on the first page; 3. After calling session_start() on another page, access the variables through the same key name; 4. Make sure that session_start() is called on each page, avoid outputting content in advance, and check that the session storage path on the server is writable; 5. Use ses
