python JSON object must be str, bytes or bytearray, not 'dict

in stackoverflow ∙ 5 mins read ∙ Tags: Python, Json, Dictionary

python JSON object must be str, bytes or bytearray, not ‘dict

  1. Question by barak manos
  2. Answer by barak manos
  3. Answer by Milovan Tomašević
    1. json.dumps() is used to decode JSON data
    2. json.loads() is used to convert JSON data into Python data.

Question by barak manos

In Python 3, to load json previously saved like this:

json.dumps(dictionary)

the output is something like

{"('Hello',)": 6, "('Hi',)": 5}

when I use

json.loads({"('Hello',)": 6, "('Hi',)": 5})

it doesn’t works, this happens:

TypeError: the JSON object must be str, bytes or bytearray, not ‘dict’

Answer by barak manos

json.loads take a string as input and returns a dictionary as output.

json.dumps take a dictionary as input and returns a string as output.

With json.loads({"('Hello',)": 6, "('Hi',)": 5}),

You are calling json.loads with a dictionary as input.

You can fix it as follows (though I’m not quite sure what’s the point of that):

d1 = {"('Hello',)": 6, "('Hi',)": 5}
s1 = json.dumps(d1)
d2 = json.loads(s1)

Answer by Milovan Tomašević

json.dumps() is used to decode JSON data

import json

# initialize different data
str_data = 'normal string'
int_data = 1
float_data = 1.50
list_data = [str_data, int_data, float_data]
nested_list = [int_data, float_data, list_data]
dictionary = {
    'int': int_data,
    'str': str_data,
    'float': float_data,
    'list': list_data,
    'nested list': nested_list
}

# convert them to JSON data and then print it
print('String :', json.dumps(str_data))
print('Integer :', json.dumps(int_data))
print('Float :', json.dumps(float_data))
print('List :', json.dumps(list_data))
print('Nested List :', json.dumps(nested_list, indent=4))
print('Dictionary :', json.dumps(dictionary, indent=4))  # the json data will be indented

output:

String : "normal string"
Integer : 1
Float : 1.5
List : ["normal string", 1, 1.5]
Nested List : [
    1,
    1.5,
    [
        "normal string",
        1,
        1.5
    ]
]
Dictionary : {
    "int": 1,
    "str": "normal string",
    "float": 1.5,
    "list": [
        "normal string",
        1,
        1.5
    ],
    "nested list": [
        1,
        1.5,
        [
            "normal string",
            1,
            1.5
        ]
    ]
}
  • Python Object to JSON Data Conversion
Python JSON
dict object
list, tuple array
str string
int, float, int- & float-derived Enums number
True true
False false
None null

json.loads() is used to convert JSON data into Python data.

import json

# initialize different JSON data
arrayJson = '[1, 1.5, ["normal string", 1, 1.5]]'
objectJson = '{"a":1, "b":1.5 , "c":["normal string", 1, 1.5]}'

# convert them to Python Data
list_data = json.loads(arrayJson)
dictionary = json.loads(objectJson)

print('arrayJson to list_data :\n', list_data)
print('\nAccessing the list data :')
print('list_data[2:] =', list_data[2:])
print('list_data[:1] =', list_data[:1])

print('\nobjectJson to dictionary :\n', dictionary)
print('\nAccessing the dictionary :')
print('dictionary[\'a\'] =', dictionary['a'])
print('dictionary[\'c\'] =', dictionary['c'])

output:

arrayJson to list_data :
 [1, 1.5, ['normal string', 1, 1.5]]

Accessing the list data :
list_data[2:] = [['normal string', 1, 1.5]]
list_data[:1] = [1]

objectJson to dictionary :
 {'a': 1, 'b': 1.5, 'c': ['normal string', 1, 1.5]}

Accessing the dictionary :
dictionary['a'] = 1
dictionary['c'] = ['normal string', 1, 1.5]
  • JSON Data to Python Object Conversion
JSON Python
object dict
array list
string str
number (int) int
number (real) float
true True
false False

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