Detailed explanation of json format control in php-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

Detailed explanation of json format control in php

*文

Dec 27, 2017 pm 05:58 PM

javascript json php

JSON is widely used in data transmission due to its high-performance transmission and analysis. This article mainly introduces relevant information on in-depth analysis of php json format control. I hope to be helpful.

Regarding the issue of json, novice friends have come to me one after another to ask, for example, why I output {"1":"item1","2":"item2","3":"item3 "} instead of ["item1","item2","item3"].

php array and js array

I use the above syntax of php 5.4 here.

There are associative arrays and index arrays in php, for example:

<?php
// 索引数组
$arr = [&#39;item1&#39;, &#39;item2&#39;, &#39;item3&#39;];
// 关联数组
$arr = [
 &#39;name&#39; => &#39;张三&#39;,
 &#39;age&#39; => &#39;22&#39;,
];

Copy after login

and js There is only one kind of array in there, and that is the index array. Maybe you will say that you can use K/V key-value pairs to simulate associative arrays.

K/V key-value pair looks like it, but it does not have any array characteristics, so it will not be explained in detail here.

The json formats obtained after json_encoding the above php array are ["item1", "item2", "item3"] and {"name":"\u5f20\u4e09","age ":"twenty two"}. The Chinese here has been converted to Unicode. If you insist on displaying Chinese, PHP 5.4 supports the JSON_UNESCAPED_UNICODE parameter. json_encode($arr, JSON_UNESCAPED_UNICODE) can get {"name":"Zhang San","age":"22" }, but it is highly not recommended to write like this.

What we get here are arrays under js and json strings in object format. So why are these two types generated? In other words, under what circumstances will object format be generated and under what circumstances will arrays be generated? What about the format.

php Array Output Format Control

I have listed the general situations, just look at the code.

<?php
$arr = [ // 不是 0 开始，会输出对象
 1 => &#39;item1&#39;,
 2 => &#39;item2&#39;,
 3 => &#39;item3&#39;,
];
echo "输出对象: ", json_encode($arr), "\n";
// 输出对象: {"1":"item1","2":"item2","3":"item3"}
$arr = [ // 连续索引，输出数组
 0 => &#39;item1&#39;,
 1 => &#39;item2&#39;,
 2 => &#39;item3&#39;,
];
echo "输出数组: ", json_encode($arr), "\n";
// 输出数组: ["item1","item2","item3"]
$arr = [ // 连续索引，输出数组 
 &#39;item1&#39;,
 &#39;item2&#39;,
 &#39;item3&#39;,
];
echo "输出数组: ", json_encode($arr), "\n";
// 输出数组: ["item1","item2","item3"]
$arr = [ // 索引不连续，输出对象
 0 => &#39;item1&#39;,
 1 => &#39;item2&#39;,
 2 => &#39;item3&#39;,
 5 => &#39;item5&#39;,
];
echo "输出对象: ", json_encode($arr), "\n";
// 输出对象: {"0":"item1","1":"item2","2":"item3","5":"item5"}
$arr = [ // 包含关联索引，一定输出对象
 0 => &#39;item1&#39;,
 1 => &#39;item2&#39;,
 2 => &#39;item3&#39;,
 &#39;other&#39; => &#39;其他字段&#39;
];
echo "输出对象: ", json_encode($arr), "\n";
// 输出对象: {"0":"item1","1":"item2","2":"item3","other":"\u5176\u4ed6\u5b57\u6bb5"}
// 关联数组 + 索引数组 实例
$arr = [ // 关联数组
 &#39;other&#39; => &#39;其他字段&#39;,
 &#39;count&#39; => 3, // 数组个数
 &#39;list&#39; => [ // 索引数组
  &#39;item1&#39;,
  &#39;item2&#39;,
  &#39;item3&#39;,
 ],
];
echo "对象+数组: ", json_encode($arr), "\n";
// 对象+数组: {"other":"\u5176\u4ed6\u5b57\u6bb5","count":3,"list":["item1","item2","item3"]}

Copy after login

In fact, the first type is a problem that many novice friends often encounter.

Because after the database is read out, they like to use the id as an index, and the id of the database does not start from 0. Take a look at this example.

$arr = $User->where($where)->find(); // 读取数据
$list = [];
foreach($arr as $key => $val) { // 遍历数组
 $list[$key] = [
  &#39;name&#39; => $val[&#39;name&#39;],
  &#39;age&#39; => $val[&#39;age&#39;],
 ];
}
$list[&#39;count&#39;] = count($arr); // 其他属性
echo json_encode($list); // 输出 json
// {"1":{"name":"zhangsan","age":22},"2":{"name":"lisi","age":25},"count":2}

Copy after login

The last one is a more common way of writing. Use custom fields and arrays together to modify the example just now.

$arr = $User->where($where)->find(); // 读取数据
$list = [];
foreach($arr as $key => $val) { // 遍历数组
 $list[&#39;list&#39;][] = [ // 修改这里
  &#39;name&#39; => $val[&#39;name&#39;],
  &#39;age&#39; => $val[&#39;age&#39;],
 ];
}
$list[&#39;count&#39;] = count($arr); // 其他属性
echo json_encode($list); // 输出 json
// {"list":[{"name":"zhangsan","age":22},{"name":"lisi","age":25}],"count":2}

Copy after login

##Related recommendations:

PHP solves the JSON Chinese display problem

php converts the index array into json

Introduction to usage examples of json_encode in php

The above is the detailed content of Detailed explanation of json format control in php. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

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

How to fix KB5055612 fails to install in Windows 10?

4 weeks ago By DDD

Roblox: Bubble Gum Simulator Infinity - How To Get And Use Royal Keys

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Roblox: Grow A Garden - Complete Mutation Guide

3 weeks ago By DDD

Nordhold: Fusion System, Explained

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Mandragora: Whispers Of The Witch Tree - How To Unlock The Grappling Hook

3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

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

Java Tutorial

1671

CakePHP Tutorial

1428

Laravel Tutorial

1331

PHP Tutorial

1276

C# Tutorial

1256

Related knowledge

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 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.

PHP: Handling Databases and Server-Side Logic Apr 15, 2025 am 12:15 AM

PHP uses MySQLi and PDO extensions to interact in database operations and server-side logic processing, and processes server-side logic through functions such as session management. 1) Use MySQLi or PDO to connect to the database and execute SQL queries. 2) Handle HTTP requests and user status through session management and other functions. 3) Use transactions to ensure the atomicity of database operations. 4) Prevent SQL injection, use exception handling and closing connections for debugging. 5) Optimize performance through indexing and cache, write highly readable code and perform error handling.

See all articles