Variables, arrays and objects are a familiar and convenient form of data representation. It is customary to describe data in the browser language JavaScript, which is not necessary in the PHP server language. The JSON format allows you to summarize them into one whole and not focus on the programming language. In this case, the data turns into pairs: “name = value”. The value in each of them can also be a collection of such pairs.

It is customary to associate JSON with curly braces and the latter is quite justified, since the JSON format = JavaScript Object Notation. Much has changed in recent particularly dynamic years. What was created for a specific purpose often brought unexpected results or opened up new horizons.

Data exchange: browser - server

AJAX technology has become traditional, regular page refresh entirely has ceased to be popular. A visitor, opening a site, initiates a series of partial data exchanges, when certain pages change only in the place that is relevant.

It is believed that the emergence of JSON is associated with the use of AJAX, but in fact, associative and its object notation (features of the syntax for describing and using objects) have a much more related relationship to JSON than the exchange of data between the browser and the server.

Since the content of the pages of modern sites has truly become “massive” (voluminous), the efficiency of the format for data exchange has acquired particular importance. This is not to say that JSON has become a new data representation, but the fact that it has long been an element of JavaScript syntax is significant.

The use of Cyrillic in naming variables is a very unexpected phenomenon (nonsense), but it works in the latest versions of Chrome, Firefox and even Internet Explorer 11.

Cyrillic and JSON

Of course, there is no point in using this completely unexpected phenomenon, remembering how easily the values ​​of variables written in Russian letters turn into gibberish: what can we say about names, especially external ones.

It is doubtful that the initiative in Cyrillic names will be supported by the external environment of the browser, with which it constantly has to deal. But this fact deserves attention for the simple reason that the JSON format is the ability to write names and values ​​as the developer wishes. This is important, since in each task the description of the application area as it requires it significantly simplifies debugging and reduces the number of errors.

It doesn’t matter what exactly the basis of the syntactic innovation - JSON - was, it is important that it gave the legal right and the real opportunity to set the correspondence: “any name = any value”.

We must pay tribute to the JavaScript language: what is provided by the syntax does not oblige the developer and does not impose anything on him. The developer freely uses the language syntax to optimally form a data model and an algorithm for their use.

PHP and JSON

By accepting data in JSON format, the server (via PHP, in particular) provides the ability to process it as is and return the result back to the browser in a similar format. PHP source array:

• $cJSON = array ("a"=> "alfa", "b"=> "beta", "g"=> "gamma").

Convert to JSON for delivery to browser:

• $cJS = json_encode($cJSON).

Result:

• ("a":"alfa","b":"beta","g":"gamma").

The nesting shown in the photo is allowed.

Here the generated array was added with a new element “into itself” with the automatic index “0”, and then again with the specified index “z”.

Json_decode() converts a JSON string to a PHP array. Similar results can be achieved by manipulating functions and explode(). In some cases this option is preferable.

Nesting level

Elements can be nested both on the browser side and on the server side. In practice, the JSON format (RFC 4627 standard description) provides significantly more than 4 levels of nesting, but this feature should not be abused.

It is best to never go beyond reasonable sufficiency; this makes the code readable, making it easier to debug and understand for other developers.

JSON is commonly referred to as data constructs that are simpler than XML and understandable to both people and computers. This is true when the amount of data is small and the developer has chosen the level of nesting wisely. In all other cases, counting the number of brackets and understanding is difficult both on the browser side and on the server side.

JSON files

The use of JSON in practice is often not limited to a human-readable short string. Any data construction is always pragmatic. At the same time, JSON can be effectively used both in real task data (enterprise staff) and for implementing temporary data (object cache).

Enterprise staff and JSON format: example

Usually a record about one person is a last name, first name, patronymic, year of birth, specialty, education, ... and a few other simple values. Even in particularly demanding companies, a record about one person will not exceed a dozen or two fields. This is perceptible and can be placed in a database string.

If a company employs several people, this is one thing, but if there are tens of thousands, this is completely different. You can continue to use the database, but storing it as a file seems more practical and accessible to use.

JSON is a plain text file. The case with the staffing table goes without saying. You can always read it. Opening and editing is also available in any text editor that does not have the habit of adding its own service information to the contents of the file. In general, *.json is pure text both inside the browser and inside the file - a string.

The photo shows the cache of the object that forms the picture, an example.

This is an example of the content of a file generated by a site that provides color 3D printing on mugs and ceramics. Naturally, having such a JSON format, deciding how to open it is really problematic. However, in this and similar cases there are no problems with reading the file: PHP reads the file, parses it and passes it to the browser. The data changed by the visitor is returned to the server and written back.

In this use case, the file acts as a variable that is stored outside of the code. If necessary, the variable receives a value from the file, and if it is changed by the visitor in the dialogue provided by the site, then all changes will be recorded as is. There is no need to read and check the contents of the file.

JSON is often used to store and use service information - this is not a staffing table, and neither the developer nor the site visitor needs to see it.

XML and JSON

“There is a time for everything” is a classical knowledge accepted as an axiom even before the advent of programming. “Nothing just appears” - this also happened before man wrote the first intelligible program in an artificial language.

Data formats arise from real needs and are based on achieved knowledge. HTML has its own path, XML has its own path, and JSON is JavaScript object logic extended to other languages. Comparing one with another is not the best thing to do. To each his own.

XML copes with its tasks wonderfully and is clearly not going to become history. And JSON was used until 2006; it’s just that not every developer considered it his duty to declare certain options for representing their data.

There have been cases in practice when programs were written in BASIC that did not use JSON as such, but perfectly stored “name = value” pairs and made them available to the right algorithms at the right time.

Special characters (“`”, “~”, “|”, ...) and data formats

The habit of working with associative arrays and objects in JavaScript makes using JSON natural and convenient. This is a really great format, but the ability to separate and join, manipulating strings and arrays, has much deeper roots.

The join/split functions of the JavaScript language and implode/explode of the PHP language allow you to conveniently and efficiently use both XML, JSON data formats, and your own version. The latter is often optimal, while the first two are ideal for general use options. If information is being transferred to another developer, server, file or database, there is no better way to find XML and JSON. Everyone works with them, so the transmission/reception of information does not require comments.

Using JSON in Android

Reading and writing data in JSON format in Android is not only the norm, but there are also many objects focused on working with this particular data format.

In this case, the JSON format is used. This may be true, but the question is not the phenomenality of social networks, but the fact that presenting information in the “name = value” format is really convenient both for programming and for use. Unlike the strict and complex “XML”, this is truly a human-friendly format.

Associative Arrays

It so happens that variables must be described (JavaScript) or at least an initial value must be specified (PHP). In both cases, the variable can change its type very easily. The language performs this conversion automatically if necessary.

But why shouldn’t the variable also change its name, appear during the execution of the algorithm, and disappear when it is no longer needed? Associative arrays solve this problem, but then when using such relatively dynamic variables, the array name and the corresponding syntactic constructs will follow where they are used.

This circumstance is especially pronounced in PHP, but you can put up with it, as, indeed, with the “$” symbol in the variable name and the “$this->” combination inside the object. Programming in JavaScript and PHP at the same time, at first you really are amazed at how different everything is, but then everything becomes so familiar and natural...

Associative Array -> JSON

In this example, a *.docx document is created using the PHPOffice/PHPWord library, and the aProperties array contains the properties of this document (author, company, title, category, creation date...).

The second array contains data for the page:

• orientation (landscape or normal);
• vertical and horizontal dimensions;
• indents (margins left, top, bottom, right);
• headers and footers.

The document is generated on the server where the PHPOffice/PHPWord library is installed. The site allows you to manage the values ​​of these arrays using JavaScript. The result in JSON format is returned back to the server and used in PHP algorithms, in its constructs, that is, in arrays.

Dynamic Variables

The JSON format solves the problem of dynamic variables. Here you can create, change and delete variables without unnecessary syntactic clutter. It looks nice and is used in JavaScript.

In this example, the GetOjInfo() function retrieves the value name and value from an object. Initially, the JSON string object assigned to the ojInfo variable has three elements: Name, age, and work. A little later the Status variable is added.

After the first delete operator, the ojInfo line loses the age element, after the second delete it loses the work element. If we assume that this string is a selection of variables that have a certain meaning, then using JSON you can actually create, change and delete any sets of them outside the operational field (syntax) of describing and processing the JavaScript language.

The JSON format was not designed for this option, but it is possible, practical and convenient.

JavaScript allows us not only to add interactivity to web pages, but it makes it possible to perform tasks that were once the responsibility of servers. JSON provides an easy way to create and store structured data in JavaScript. JSON is very popular and is a great alternative to XML. JSON (JavaScript Object Notation), as the name suggests, is based on the creation of javascript objects. JavaScript objects can be easily manipulated and parsed using the same JavaScript.

Unlike XML, JSON sentences are easily composed by both humans and computers. Data in JSON format can, for example, be assigned to a variable (this is how we create an object); this data can then be read through the newly created object.

var data=( "firstName" : "Ray" ); alert(data.firstName);

First, we create a variable to hold our data, and then we use JSON to define an object. Our object is quite simple: a firstName field and a Ray value. Strings in JSON must be enclosed in quotes. If you are using numbers, quotes are optional.

This example will display the value of the firstName property in the browser.

Creating a placeholder object

Let's create a more realistic example: insert our JSON data into a DOM object.

var data=("firstName":"Ray"); document.getElementById("placeholder").innerHTML=data.firstName;

Now, instead of displaying a warning, we put the data inside the HTML element. JSON data, of course, can be much more complex. Let's try adding a few more fields.

data=( "firstName":"Ray", "lastName":"Villalobos", "joined":2012 ); document.getElementById("placeholder").innerHTML=data.firstName+" "+data.lastName+" "+data.joined;

Note that the JSON data is formatted in a specific way for better understanding. The "joined" field has the value 2012, which does not require quotes since it is a number. Let's look at something more complex.

Adding arrays

What if we want to enter a group of people...then we need to use arrays. An array in JSON can be created using square brackets. Let's see how our data will look for multiple users.

Var data=("users":[ ( "firstName":"Ray", "lastName":"Villalobos", "joined":2012 ), ( "firstName":"John", "lastName":"Jones", "joined":2010 ) ]) document.getElementById("placeholder").innerHTML=data.users.firstName + " " + data.users.lastName+" "+ data.users.joined;

Looks a little complicated, but is actually not difficult to understand. A JSON object is created using curly braces; an array is created using square brackets. So, to organize our data, we created a users object, which we placed an array into. The array contains other objects. Each (name/value) pair is separated by a comma.

Notice how the code for inserting the name has changed. We connected the new users object and then used square brackets to point to the first element in the array. Let's add one more level to the structure of our data.

Var data=("users":[ ( "firstName":"Ray", "lastName":"Villalobos", "joined": ( "month":"January", "day":12, "year":2012 ) ), ( "firstName":"John", "lastName":"Jones", "joined": ( "month":"April", "day":28, "year":2010 ) ) ]) document. getElementById("placeholder").innerHTML=data.users.firstName + " " + data.users.lastName+"--"+ data.users.joined.month;

The joined property now contains an object with multiple fields; There is no need to use an array, so we use object notation. Now we have data for several users, it's time to go through each user and display them in the list.

Implementing a list of users (passing through the JSON object)

So, let's use javascript and create a list of users.

Var data = ( "users":[ ( "firstName":"Ray", "lastName":"Villalobos", "joined": ( "month":"January", "day":12, "year":2012 ) ), ( "firstName":"John", "lastName":"Jones", "joined": ( "month":"April", "day":28, "year":2010 ) ) ]) var output ="

"; ) output+="

"; document.getElementById("placeholder").innerHTML=output;

To iterate through all the properties of an object, there is a for..in construction:

For(var key in object) ( // key - property name // object - property value... )

Here we go through all the elements of the array; we save the data in the output variable and place the data in an element with id equal to placeholder . you can tell that our data is building a little slow.

Reading JSON from an external file

It would be nice to save the data to an external file and read it as needed. I'm going to use the jQuery library and so first we need to include the jQuery library; then we call the getJSON function. This is what our code looks like:

JSON Sample $.getJSON("data.json", function(data) ( var output="

"; for (var i in data.users) ( output+="
• " + data.users[i].firstName + " " + data.users[i].lastName + "--" + data.users[i].joined.month+"
"; ) output+="

"; document.getElementById("placeholder").innerHTML=output; ));

It's pretty much the same code, but the data is brought out. We simply wrapped everything up with a getJSON function that does all the hard work of reading the file. The data file data.json, suppose, is located in the same directory and looks like this:

("users":[ ( "firstName":"Ray", "lastName":"Villalobos", "joined": ( "month":"January", "day":12, "year":2012 ) ), ( "firstName":"John", "lastName":"Jones", "joined": ( "month":"April", "day":28, "year":2010 ) ) ])

As you can see, JSON is really easy to read, and once you get used to the parentheses, it becomes easy to code.

If you have an antivirus program installed on your computer, you can scan all files on the computer, as well as each file individually. You can scan any file by right-clicking on the file and selecting the appropriate option to scan the file for viruses.

For example, in this figure the file my-file.json is highlighted, then you need to right-click on this file and select the option “scan with AVG” in the file menu. When you select this option, AVG Antivirus will open and scan the file for viruses.

Sometimes the error may occur as a result of the software being installed incorrectly, which may be due to a problem encountered during the installation process. This may prevent your operating system from associating your JSON file with the correct application software, affecting what are called "file extension associations".

Sometimes simply reinstalling Mozilla Firefox can solve your problem by binding JSON correctly to Mozilla Firefox. In other cases, problems with file associations may result from poor programming of the software by the developer, and you may need to contact the developer for further assistance.

Tip: Try updating Mozilla Firefox to the latest version to ensure you have the latest patches and updates.

This may seem too obvious, but often the JSON file itself can be the cause of the problem. If you received a file via an email attachment or downloaded it from a website, and the download process was interrupted (such as a power outage or other reason), the file may become corrupted. If possible, try getting a new copy of the JSON file and try opening it again.

Caution: A corrupted file may cause collateral damage from previous or existing malware on your PC, so it is important to keep your computer running an updated antivirus at all times.

If your JSON file is associated with hardware on your computer, you may need to update the device drivers associated with that hardware in order to open the file.

This problem is usually associated with media file types that depend on successfully opening hardware inside the computer, such as a sound card or video card. For example, if you are trying to open an audio file but cannot open it, you may need to update your sound card drivers.

Tip: If you receive an error message related to .SYS file when you try to open a JSON file, the problem may likely be due to corrupt or outdated device drivers that need to be updated. This process can be made easier by using driver update software such as DriverDoc.

If the steps did not resolve the issue and you are still having trouble opening JSON files, it may be due to a lack of available system resources. Some versions of JSON files may require a significant amount of resources (e.g. memory/RAM, processing power) to properly open on your computer. This problem is quite common if you are using fairly old computer hardware and at the same time a much newer operating system.

This problem can occur when the computer is having trouble keeping up with the task because the operating system (and other services running in the background) may be consuming too many resources to open the JSON file. Try closing all applications on your PC before opening Mozilla Firefox Bookmarks Backup. Freeing up all available resources on your computer will provide the best conditions for attempting to open the JSON file.

If you've followed all the steps above and your JSON file still won't open, you may need to perform a hardware update. In most cases, even when using older versions of hardware, the processing power can still be more than sufficient for most user applications (unless you're doing a lot of CPU-intensive work, such as 3D rendering, financial/scientific modeling, or intensive multimedia work) . Therefore, it is likely that your computer does not have enough memory (more commonly called "RAM" or random access memory) to complete the task of opening a file.

Json was created for JavaScript (its full name is JavaScript Object Notation), and it is a data exchange format.

Json has found its use in various programming languages ​​- for example, in PHP, where it looks like this:

["1":"yellow";"2":"green";"3":"grey"]

The example shows that there are no spaces, and the name and value are enclosed in double quotes. If the length allows, the string can be used to transfer data in the GET method.

In this case, the transmitted array can have a multi-level structure. PHP has a set of json functions designed to create and decode such strings and work exclusively with UTF-8.

Json_encode in php This function converts an object, array or variable into json format. The following example will convert an array to this format. ?> Json_decode in php This function decodes the received string and depending on which option was selected we get an object or an array. The function has two parameters - mandatory (a string to be decrypted) and optional (if you specify it, an array will be output, if not, an object). Consider the following example. Getting data from a class: Getting data from an array: Json_last_error in php

This function has no parameters. It returns a value that identifies the cause of errors.

• JSON_ERROR_NONE - No errors
• JSON_ERROR_SYNTAX - Syntax error
• JSON_ERROR_UTF8 - Incorrect UTF-8 characters, possibly incorrect encoding
• JSON_ERROR_DEPTH - Maximum stack depth reached
• JSON_ERROR_STATE_MISMATCH - Invalid or incorrect JSON
• JSON_ERROR_CTRL_CHAR - Control character error, possibly incorrect encoding

People familiar with programming will immediately recognize files with the JSON extension. This format is an abbreviation of JavaScript Object Notation, and is essentially a text-based data exchange used in the JavaScript programming language. Accordingly, either specialized software or text editors will help you cope with opening such files.

The main feature of scripts in the JSON format is its interchangeability with the XML format. Both types are text documents that can be opened by word processors. However, we will start with specialized software.

Method 1: Altova XMLSpy

A fairly well-known development environment, which is also used by web programmers. This environment also generates JSON files and is therefore capable of opening third-party documents with this extension.

This software has two disadvantages. The first is a paid distribution basis. The trial version is active for 30 days, but to receive it you must provide a name and email address. The second is general cumbersomeness: to a person who just needs to open a file, it may seem too sophisticated.

Method 2: Notepad++

The multifunctional text editor Notepad++ is the first in the list of scripts suitable for opening JSON format.

Notepad++ has a lot of advantages - it displays the syntax of many programming languages, supports plugins, and is small in size... However, due to some features, the program works slowly, especially if you open a large document in it.

Method 3: AkelPad

An incredibly simple and at the same time rich in capabilities text editor from a Russian developer. The formats it supports include JSON.

Like Notepad++, this notepad option is also free and supports plugins. It works faster, but large and complex files may not open the first time, so keep this feature in mind.

Method 4: Komodo Edit

Free software for writing program code from Komodo. It features a modern interface and broad support for programmers.

Unfortunately, the program does not have Russian language. However, the average user will be more likely to be put off by the excessive functionality and incomprehensible interface elements - after all, this editor is aimed primarily at programmers.

Method 5: Sublime Text

Another representative of code-oriented text editors. The interface is simpler than that of its colleagues, but the capabilities are the same. A portable version of the application is also available.

Unfortunately, Sublime Text is not available in Russian. The shareware distribution model can also be called a disadvantage: the free version is not limited in any way, but from time to time a reminder appears about the need to purchase a license.

Method 6: NFOPad

A simple notepad is also suitable for viewing documents with the JSON extension.