Python JSON
JSON is a syntax for storing and exchanging data.
JSON is text, written with JavaScript object notation.
JSON in Python
Python has a built-in package called json, which can be used to work with JSON data.
Example
Import the json module:
import json
Parse JSON - Convert from JSON to Python
If you have a JSON string, you can parse it by using the json.loads() method.
The result will be a Python dictionary.
Example
Convert from JSON to Python:
import json
# some JSON:
x = '{ "name":"John", "age":30, "city":"New York"}'
# parse x:
y = json.loads(x)
# the result is a Python dictionary:
print(y["age"])
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Convert from Python to JSON
If you have a Python object, you can convert it into a JSON string by using the json.dumps() method.
Example
Convert from Python to JSON:
import json
# a Python object (dict):
x = {
"name": "John",
"age": 30,
"city": "New York"
}
# convert into JSON:
y = json.dumps(x)
# the result is a JSON string:
print(y)
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You can convert Python objects of the following types, into JSON strings:
- dict
- list
- tuple
- string
- int
- float
- True
- False
- None
Example
Convert Python objects into JSON strings, and print the values:
import json
print(json.dumps({"name": "John", "age": 30}))
print(json.dumps(["apple", "bananas"]))
print(json.dumps(("apple", "bananas")))
print(json.dumps("hello"))
print(json.dumps(42))
print(json.dumps(31.76))
print(json.dumps(True))
print(json.dumps(False))
print(json.dumps(None))
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When you convert from Python to JSON, Python objects are converted into the JSON (JavaScript) equivalent:
| Python | JSON |
|---|---|
| dict | Object |
| list | Array |
| tuple | Array |
| str | String |
| int | Number |
| float | Number |
| True | true |
| False | false |
| None | null |
Example
Convert a Python object containing all the legal data types:
import json
x = {
"name": "John",
"age": 30,
"married": True,
"divorced": False,
"children": ("Ann","Billy"),
"pets": None,
"cars": [
{"model": "BMW 230", "mpg": 27.5},
{"model": "Ford Edge", "mpg": 24.1}
]
}
print(json.dumps(x))
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Format the Result
The example above prints a JSON string, but it is not very easy to read, with no indentations and line breaks.
The json.dumps() method has parameters to make it easier to read the result:
Example
Use the indent parameter to define the numbers of indents:
json.dumps(x, indent=4)
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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:
Example
Use the separators parameter to change the default separator:
json.dumps(x, indent=4, separators=(". ", " = "))
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Order the Result
The json.dumps() method has parameters to order the keys in the result:
Example
Use the sort_keys parameter to specify if the result should be sorted or not:
json.dumps(x, indent=4, sort_keys=True)
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