Encoding and Decoding JSON with Python — A Cheatsheet
Conversion of json string (or json file) to python and vice versa is often a confusing endeavor. This article can serve as a cheatsheet.
In this short post, I provide a highlight of the conversion functions from json to python and vice versa. The functions are:
- json.loads(jsonString) — json string to python object
- json.dumps(pythonObject) — python object to json string
- json.load(fileHandler) — json file to python object — python object from file
- json.dump(jsonString or pythonObject, fileHandler) — json string or python object to json file
When you want to access json elements using their keys, you need to convert a json string or a json file into a python dictionary with json.loads(json string) or json.dumps(file handler), respectively. Note the s in loads — which perhaps stands for string, thus loads == loadString.
Similarly, when you want to convert a python dictionary to a json string, e.g., for string processing, or want to save it as a json file, you use json.load(python_dict) or json.dump(json string or python object, file handler), respectively. The following code snippets demonstrates these functions. But first of all, you need to import the required library, i.e., json.
import json- json.loads()
json_string = '{"name": "John Due", "ID": 123456}'
#print(json_string["name"]) #TypeError: string indices must be integers
json_dict = json.loads(json_string)#type(json_string) # <class 'str'>
#type(json_dict) # <class 'dict'>print(json_dict["name"])
the above code produces:
John Due
2. json.dumps()
json_string_1 = json.dumps(json_dict, indent=5)
#print("Json_dict" + json_dict) #TypeError: can only concatenate str (not "dict") to str#type(json_string_1) # <class 'str'>
print(json_string_1)
the above code snippet produces:
{
"name": "John Due",
"ID": 123456
}
3. json.dump()
# writes in file a json string: "{\"name\": \"John Due\", \"ID\": 123456}"
with open("json_file.json", "w") as json_file:
json.dump(json_string, json_file)# writes in file a json object: {"name": "John Due", "ID": 123456}
with open("json_file1.json", "w") as json_file1:
json.dump(json_dict, json_file1)
4. json.load()
with open("json_file.json", "r") as json_file:
file_content = json.load(json_file)
#type(file_content) # <class 'str'>print(file_content)
with open("json_file1.json", "r") as json_file1:
file_content_1 = json.load(json_file1)
#type(file_content_1) # <class 'dict'>print(file_content_1)
The above code snippet produces
{"name": "John Due", "ID": 123456}
{'name': 'John Due', 'ID': 123456}
I hope this article give a summary of the four functions that are often used for encoding and decoding json data. Drop me a question or feedback, if you have one, in the comment section.
