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Outline
? What is JSON?
? Syntax
? Example
? Schema
? Validating JSON file
? Using JSON with Python
? Writing a JSON file
? Reading a JSON
? Accessing JSON Properties in Python

What is JSON?
? “JSON” stands for “JavaScript Object Notation”
? Lightweight data-interchange format
? Despite the name, JSON is a (mostly) language-
independent way of specifying objects as name-value
pairs
? Structured representation of data object
? Can be parsed with most modern languages
? JSON Schema can be used to validated a JSON
file

JSON Syntax Rules
? JSON is almost identical to python dictionary except for
? In JSON, true and false are not capitalized
? In JSON, null is used instead of None
? Uses key/value pairs: {“name”: “John”}
? Uses double quotes around KEY and VALUE
? Must use the specified types
? File type is “.json”
? A value can be: A string, a number, true, false, null, an
object, or an array
? Strings are enclosed in double quotes, and can contain
the usual assortment of escaped characters

JSON Example
{
"name": "John Smith",
"age": 35,
"address": {
"street": "5 main St.",
"city": "Austin"
},
"children": ["Mary", "Abel"]
}

JSON Schema
? A JSON Schema allows you to specify what type of
data can go into your JSON files.
? It allows you to restrict the type of data entered.

JSON Schema
{
"type": "object",
"properties": {
"name": {
"type": "string"
},
"age": {
"type": "integer"
},
"address": {
"type": "object",
"properties": {
"street": {
"type": "string"
},
"city": {
"type": "string"
}
}
"children": {
"type": "array",
"items": {
"type": "string
}
}
}
}

Validating JSON file
? The following website can be used to validate a JSON
file against a schema
https://www.jsonschemavalidator.net/
? Paste both the schema and the corresponding JSON file

Using JSON with Python
? To work with JSON (string, or file containing JSON
object), you can use Python's json module.
import json

Loading JSON data from a file
? Example:
def load_json(filename):
with open(filename) as file:
jsn = json.load(file)
#file.close()
return jsn
person = load_json('person.json')
? This command parse the above person.json using
json.load() method from the json module. The result is a
Python dictionary.

Writing JSON object to a file
? Example:
person = { "name": "John Smith", "age": 35,
"address": {"street": "5 main St.", "city":
"Austin"}, "children": ["Mary", "Abel"]}
with open('person_to_json.json', 'w') as fp:
json.dump(person, fp, indent=4)
? Using json.dump(), we can convert Python Objects to
JSON file.

Accessing JSON Properties in Python
? Example:
Assume that you already loaded your person.json as
follows.
To access the property "name"
? Print(person["name"])
? John Smith

? Example:
follows.
To access the property “age"
? person["age"]
? 35

? Example:
follows.
To access the property “street"
? print(person["address"]["street"])
? 5 main St.

? Example:
follows.
? print(person["address"]["city"])
? Austin

? Example:
follows.
? print(person["children"][0])
? Mary

? Example:
follows.
? print(person["children"][1])
? Abel

Credit:
? https://www.youtube.com/watch?v=wI1CWzNtE-M
? https://www.programiz.com/python-programming/json

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JSON(JavaScript Object Notation) Presentation transcript

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JSON(JavaScript Object Notation) Presentation transcript