When a program needs to exchange data or preserve Python structures on disk, JSON provides a text representation that other languages can read. Web services and APIs commonly send and receive it. section 5.26 section 5.0
JSON is a data representation rather than a Python data type. Python's json module converts JSON text into built-in objects such as lists and dicts, and converts Python data back into JSON-formatted strings. Use json.load for a file object, json.loads for a string, and the corresponding dump functions when writing. section 5.27 section 5.36
A practical JSON-processing workflow is:
- Find relevant files, for example with glob.glob('scores/*.json'). section 5.27
- Open each file and call json.load to obtain Python data structures. section 5.26
- Transform the resulting lists and dicts, then calculate or organize the required results. section 5.27
- Write transformed data with json.dump when a JSON file is the desired output. section 5.36
Summarizing class scores
Given files such as scores/9a.json and scores/9b.json, read each JSON array of subject-score dictionaries, collect scores by subject, and print each class's minimum, maximum, and average. JSON requires double quotes, not Python's single quotes. section 5.26
[{"math" : 90, "literature" : 98, "science" : 97},
{"math" : 65, "literature" : 79, "science" : 85},
{"math" : 78, "literature" : 83, "science" : 75},
{"math" : 92, "literature" : 78, "science" : 85},
{"math" : 100, "literature" : 80, "science" : 90}
]
Inspect a complete JSON array of dictionaries representing student scores. section 5.26
