Hướng dẫn dùng json w3schools python
JSON is a syntax for storing and exchanging data. Show JSON is text, written with JavaScript object notation. JSON in PythonPython has a built-in package called ExampleImport the json module: import json Parse JSON - Convert from JSON to PythonIf you have a JSON string, you can parse it by using the ExampleConvert from JSON to Python: import json # some JSON: # parse x: # the result is a Python dictionary: Try it Yourself » Convert from Python to JSONIf you have a Python object, you can convert it into a JSON string by using the ExampleConvert from Python to JSON: import json # a Python object (dict): # convert into JSON: # the result is a JSON string: Try it Yourself » You can convert Python objects of the following types, into JSON strings:
ExampleConvert Python objects into JSON strings, and print the values: import json print(json.dumps({"name": "John", "age": 30})) Try it Yourself » When you convert from Python to JSON, Python objects are converted into the JSON (JavaScript) equivalent:
ExampleConvert a Python object containing all the legal data types: import json x = { print(json.dumps(x)) Try it Yourself » Format the ResultThe example above prints a JSON string, but it is not very easy to read, with no indentations and line breaks. The ExampleUse the json.dumps(x, indent=4) Try it Yourself » You can also define the separators, default value is (", ", ": "), which means using a comma and a space to separate each object, and a colon and a space to separate keys from values: ExampleUse the json.dumps(x, indent=4, separators=(". ", " = ")) Try it Yourself » Order the ResultThe ExampleUse the json.dumps(x, indent=4, sort_keys=True) Try it Yourself » W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy. Copyright 1999-2022 by Refsnes Data. All Rights Reserved. A common use of JSON is to read data from a web server, and display the data in a web page. This chapter will teach you how to exchange JSON data between the client and a PHP server. The PHP FilePHP has some built-in functions to handle JSON. Objects in PHP can be converted into JSON by using the PHP function json_encode(): PHP file$myObj->name = "John"; $myJSON = json_encode($myObj); echo $myJSON; Show PHP file » The Client JavaScriptHere is a JavaScript on the client, using an AJAX call to request the PHP file from the example above: ExampleUse JSON.parse() to convert the result into a JavaScript object: const xmlhttp = new XMLHttpRequest(); Try it Yourself » PHP ArrayArrays in PHP will also be converted into JSON when using the PHP function json_encode(): PHP file$myArr = array("John", "Mary", "Peter", "Sally"); $myJSON = json_encode($myArr); echo $myJSON; Show PHP file » The Client JavaScriptHere is a JavaScript on the client, using an AJAX call to request the PHP file from the array example above: ExampleUse JSON.parse() to convert the result into a JavaScript array: var xmlhttp = new XMLHttpRequest(); Try it Yourself » PHP DatabasePHP is a server side programming language, and can be used to access a database. Imagine you have a database on your server, and you want to send a request to it from the client where you ask for the 10 first rows in a table called "customers". On the client, make a JSON object that describes the numbers of rows you want to return. Before you send the request to the server, convert the JSON object into a string and send it as a parameter to the url of the PHP page: ExampleUse JSON.stringify() to convert the JavaScript object into JSON: const limit = {"limit":10}; Try it Yourself » Example explained:
Take a look at the PHP file: PHP fileheader("Content-Type:
application/json; charset=UTF-8"); $conn = new mysqli("myServer", "myUser", "myPassword", "Northwind"); echo json_encode($outp); PHP File explained:
Use the DataExample xmlhttp.onload = function() { Try it Yourself » PHP Method = POSTWhen sending data to the server, it is often best to use the HTTP To send AJAX requests using the The data sent to the server must now be an argument to the Example const
dbParam = JSON.stringify({"limit":10}); Try it Yourself » The only difference in the PHP file is the method for getting the transferred data. PHP fileUse $_POST instead of $_GET: header("Content-Type: application/json; charset=UTF-8"); echo json_encode($outp); |