#Json-CPP A better json library.
pip install json-cpp
After installing the package, try the following python script:
from json_cpp import JsonObject
myobject = JsonObject(name="German Espinosa",age=41,weight=190.0)
print("name:", myobject.name, type(myobject.name).__name__)
print("age:", myobject.age, type(myobject.age).__name__)
print("weight:", myobject.weight, type(myobject.weight).__name__)
print(myobject)
output
name: German Espinosa str
age: 41 int
weight: 190.0 float
{"name":"German Espinosa","age":41,"weight":190.0}
To quickly load json data into objects, use the load command:
from json_cpp import JsonObject
myobject = JsonObject.load("{\"name\":\"German Espinosa\",\"age\":41,\"weight\":190.0}")
print("name:", myobject.name, type(myobject.name).__name__)
print("age:", myobject.age, type(myobject.age).__name__)
print("weight:", myobject.weight, type(myobject.weight).__name__)
output
name: German Espinosa str
age: 41 int
weight: 190.0 float
You can easily format data, even in complex json hierarchical structures:
from json_cpp import JsonObject
myobject = JsonObject.load("{\"name\":\"German Espinosa\",\"age\":41,\"weight\":190.0,\"place_of_birth\":{\"country\":\"Argentina\",\"city\":\"Buenos Aires\"}}")
print(myobject.format("{name} was born in {place_of_birth.city}, {place_of_birth.country}"))
output
German Espinosa was born in Buenos Aires, Argentina
A powerful way to read and write json is to pre-define the structure of the data. This creates standarized data samples that are easire to be consumed by other tools. To pre-define structure of a json object, you need to create your own custom class extending the JsonObject:
from json_cpp import JsonObject
class MyJsonClass(JsonObject):
def __init__(self, name="", age=0, weight=0.0):
self.name = name
self.age = age
self.weight = weight
myobject = MyJsonClass('German Espinosa', 41, 190.0)
json_string = str(myobject)
print(json_string)
output
{"name":"German Espinosa","age":41,"weight":190.0}
You can also load values from a json string directly into an existing custom JsonObject:
from json_cpp import JsonObject
class MyJsonClass(JsonObject):
def __init__(self, name="", age=0, weight=0.0):
self.name = name
self.age = age
self.weight = weight
myobject = MyJsonClass('German Espinosa', 41, 190.0)
myobject.parse("{\"name\":\"Benjamin Franklin\",\"age\":84,\"weight\":195.5}")
json_string = str(myobject)
print(json_string)
output
{"name":"Benjamin Franklin","age":84,"weight":195.5}
All objects with type MyJsonClass will produce perfectly formed json when converted to string. If you need to retrieve the json string representing the object:
from json_cpp import JsonObject
class MyJsonClass(JsonObject):
def __init__(self, name="", age=0, weight=0.0):
self.name = name
self.age = age
self.weight = weight
myobject = MyJsonClass('German Espinosa', 41, 190.0)
json_string = str(myobject)
print (json_string)
output
{"name":"German Espinosa","age":41,"weight":190.0}
You can create instances of your json objects from strings containing a correct json representation:
from json_cpp import JsonObject
class MyJsonClass(JsonObject):
def __init__(self, name="", age=0, weight=0.0):
self.name = name # string
self.age = age # int
self.weight = weight # float
json_string = "{\"name\":\"German Espinosa\",\"age\":41,\"weight\":190.0}"
myobject = MyJsonClass.parse(json_string)
print("name:", myobject.name, type(myobject.name).__name__)
print("age:", myobject.age, type(myobject.age).__name__)
print("weight:", myobject.weight, type(myobject.weight).__name__)
output
name: German Espinosa str
age: 41 int
weight: 190.0 float
note: all members are populated with the right values using the same data type declared in the default constructor of the class
You can create complex structures with nested objects:
from json_cpp import JsonObject
class Person(JsonObject):
def __init__(self, name="", age=0):
self.name = name
self.age = age
class Transaction(JsonObject):
def __init__(self, buyer=None, seller=None, product="", amount=0.0):
self.buyer = buyer if buyer else Person()
self.seller = seller if seller else Person()
self.product = product
self.amount = amount
mytransaction = Transaction(Person("German Espinosa", 41), Person("Benjamin Franklin", 84), "kite", 150.5)
print (mytransaction)
output
{"buyer":{"name":"German Espinosa","age":41},"seller":{"name":"Benjamin Franklin","age":84},"product":"kite","amount":150.5}
You can load full lists with values from a json string to a JsonList:
from json_cpp import JsonObject, JsonList
fibonacci = JsonList(list_type=int)
json_string = "[1,1,2,3,5,8,13,21]"
fibonacci.parse(json_string)
You can also load a list of json objects:
from json_cpp import JsonObject, JsonList
class Person(JsonObject):
def __init__(self, name="", surname=""):
self.name = name
self.surname = surname
person_list = JsonList(list_type=Person)
json_string = "[{\"name\":\"german\",\"surname\":\"espinosa\"},{\"name\":\"benjamin\",\"surname\":\"franklin\"}]"
person_list.parse(json_string)
Lists can also be used as members of other objects:
from json_cpp import JsonObject, JsonList
class Person(JsonObject):
def __init__(self):
self.name = ""
self.surname = ""
self.languages = JsonList(list_type=str)
person = Person.parse("{\"name\":\"German\",\"surname\":\"Espinosa\", \"languages\":[\"english\",\"spanish\",\"portuguese\"]}")
print(person)
output
{"name":"German","surname":"Espinosa","languages":["english","spanish","portuguese"]}