Backend Development
PHP Tutorial
The difference between PHP merge array array_merge function operator plus sign and - PHP tutorial
The difference between PHP merge array array_merge function operator plus sign and - PHP tutorial
The description of array_merge in the reference manual is as follows:
array_merge() Merges the cells of two or more arrays, and the values in one array are appended to the previous array. Returns the resulting array.
If there is the same string key name in the input array, the value after the key name will overwrite the previous value. However, if the array contains numeric keys, the subsequent values will not overwrite the original values but will be appended to them.
The difference between the two is:
1. When the array key name is a numeric key name, and the two arrays to be merged have numeric KEYs with the same name, using array_merge() will not overwrite the original value. Using "+" to merge arrays will return the first appearing value as the final result, and "discard" those values with the same key name in subsequent arrays (note: not overwriting but retaining the first appearing value) . Example:
$array1 = array(1=>'0');
$array2 = array(1=> "data");
$result1 = $array2 + $array1;/*The result is the value of $array2*/
print_r($result);
$ result = $array1 + $array2 ;/*The result is the value of $array1*/
print_r($result);
$result3 = array_merge($array2,$array1);/*The result is $array2 and $ The value of array1, the key name is reassigned*/
print_r($result3);
$result4 = array_merge($array1,$array2);/*The result is the value of $array1 and $array2, the key name is Reassign*/
print_r($result4);
The output result is:
Array
(
[1] => data
)
Array
(
[1] => 0
)
Array
(
[0] => data
[1] => 0
)
Array
(
[0] => 0
[1] => data
)
2. When the same array key name is a character, the "+" operator is the same as when the key name is a number, but array_merge() At this time, the previous value with the same key name will be overwritten.
Example:
');
$result4 = array_merge($array1,$array2);/*The result is $array2*/
print_r($result4);
The output result is:
Copy code
The code is as follows:
Array
Array
(
[asd] => ; 0
)
Array
(
[asd] => data
)
http://www.bkjia.com/PHPjc/319608.html
www.bkjia.com
http: //www.bkjia.com/PHPjc/319608.html
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
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
1664
14
1423
52
1317
25
1268
29
1246
24
PHP and Python: Different Paradigms Explained
Apr 18, 2025 am 12:26 AM
PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.
Choosing Between PHP and Python: A Guide
Apr 18, 2025 am 12:24 AM
PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.
PHP and Python: A Deep Dive into Their History
Apr 18, 2025 am 12:25 AM
PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.
Why Use PHP? Advantages and Benefits Explained
Apr 16, 2025 am 12:16 AM
The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.
PHP's Impact: Web Development and Beyond
Apr 18, 2025 am 12:10 AM
PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip
PHP vs. Python: Use Cases and Applications
Apr 17, 2025 am 12:23 AM
PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.
The Continued Use of PHP: Reasons for Its Endurance
Apr 19, 2025 am 12:23 AM
What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.
PHP: An Introduction to the Server-Side Scripting Language
Apr 16, 2025 am 12:18 AM
PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.
