Backend Development
PHP Tutorial
What are the ways to merge arrays in PHP and retain key values?
What are the ways to merge arrays in PHP and retain key values?
This time I will bring you some methods to merge arrays in PHP and retain key values? , what are the precautions to implement PHP merging arrays and retaining key values? The following is a practical case, let's take a look.
php merges arrays, generally using the array_merge method.
array_merge — Merge one or more arrays
array array_merge ( array $array1 [, array $... ] )
array_merge Merges the cells of one or more arrays. The values in one array are appended to the previous array and returned as the result. 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 latter will not overwrite the original value, but will be appended to it.
If only an array is given and the array is numerically indexed, the key names are re-indexed in a consecutive manner.
Example 1, array uses string key name, the same key name will be overwritten by the following
<?php
$arr1 = array('name'=>'fdipzone');
$arr2 = array('name'=>'terry');
$result = array_merge($arr1, $arr2);
print_r($result);
?>Output:
Array ( [name] => terry )
Example 2, the array uses numeric key names, the same key names will not be overwritten, and the key names will be re-indexed
<?php $arr1 = array(0=>'fdipzone',1=>'terry'); $arr2 = array(0=>'php',1=>'python'); $result = array_merge($arr1, $arr2); print_r($result); ?>
Output:
Array ( [0] => fdipzone [1] => terry [2] => php [3] => python )
Due to work needs, the answers to the two parts of the multiple-choice questions in the questionnaire need to be merged together. The answers to each part are arrays (key=>value), key is the question number, value is the answer, and There is no duplication of question numbers in the two parts.
Use array_merge to merge the two parts of the answer
<?php $form_data1 = array(11=>'A',12=>'B',13=>'C',14=>'D'); $form_data2 = array(25=>'B',26=>'A',27=>'D',28=>'C'); $result = array_merge($form_data1, $form_data2); print_r($result); ?>
Output:
Array ( [0] => A [1] => B [2] => C [3] => D [4] => B [5] => A [6] => D [7] => C )
Use array_merge to merge, because the question number (key) is a number, so the key name will be re-indexed, resulting in the question The number cannot be reserved.
Method to merge arrays and keep key values:
<?php $form_data1 = array(11=>'A',12=>'B',13=>'C',14=>'D'); $form_data2 = array(25=>'B',26=>'A',27=>'D',28=>'C'); $result = $form_data1 + $form_data2; print_r($result); ?>
Output:
Array ( [11] => A [12] => B [13] => C [14] => D [25] => B [26] => A [27] => D [28] => C )
Use " " The operator merges arrays and can retain the key values of the array. If the merged array contains the same key value, the later one will not overwrite the previous key value (the previous one takes precedence).
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
Recommended reading:
What are the ways to generate complex verification codes in PHP
Detailed explanation of the steps to implement routing and class automatic loading in PHP
The above is the detailed content of What are the ways to merge arrays in PHP and retain key values?. For more information, please follow other related articles on the PHP Chinese website!
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
1669
14
1428
52
1329
25
1273
29
1256
24
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
PHP vs. Python: Understanding the Differences
Apr 11, 2025 am 12:15 AM
PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
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.
PHP vs. Other Languages: A Comparison
Apr 13, 2025 am 12:19 AM
PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.
PHP and Python: Code Examples and Comparison
Apr 15, 2025 am 12:07 AM
PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.
