How to read a JSON file in Python?
Reading JSON files can be implemented in Python through the json module. The specific steps are: use the open() function to open the file, use json.load() to load the content, and the data will be returned in a dictionary or list form; if you process JSON strings, you should use json.loads(). Common problems include file path errors, incorrect JSON format, encoding problems and data type conversion differences. Pay attention to path accuracy, format legality, encoding settings, and mapping of boolean values and null.

Reading JSON files is actually quite common in Python, especially when handling configuration files, API responses, or data exchange. Python's own json module is enough to complete most operations and does not require additional installation of libraries.

Loading JSON files using json module
The most direct way in Python is to use the json module in the standard library. This module provides several common functions, such as json.load() and json.loads() , which are used to parse JSON data from file objects and strings, respectively.
To read a local JSON file, the basic process is as follows:

- Open the file (usually using
open()function) - Use
json.load()to load content - The resulting data will be of dictionary or list type, depending on the structure of the original JSON
For example, suppose you have a file named data.json with the content like this:
{
"name": "Alice",
"age": 30,
"is_student": false
}You can read it with the following code:

import json
with open('data.json', 'r') as file:
data = json.load(file)
print(data['name']) # output AliceThis method is simple and practical, suitable for most situations.
Tips for handling JSON strings
Sometimes you get a JSON format string, not a file. At this time, you cannot use json.load() , but json.loads() . Note that s represents string here.
For example:
json_str = '{"name": "Bob", "age": 25}'
data = json.loads(json_str)
print(data['age']) # Output 25 This scenario is common for extracting data from the response body returned by a network request, such as using requests library to obtain the content returned by the API interface.
Problems that are easy to encounter when reading JSON
Although reading JSON seems simple, you may still encounter some small pitfalls during actual use:
- File path error : Make sure that the file name and path you open are correct, especially the difference between relative and absolute paths.
- JSON format is incorrect : If the JSON content format is incorrect (such as few commas and quotes are not closed),
json.load()will throw an exception. - Coding issues : Some JSON files may be encoding other than UTF-8. You can specify
encoding='utf-8'inopen()to avoid error reports. - Data type conversion problem : For example,
true/falsein JSON will becomeTrue/Falsein Python, andnullwill becomeNone. Pay attention to these mapping relationships.
If you are not sure whether JSON is legal, you can first verify the format with online tools.
Basically that's it. The whole process is not complicated, but if you are not careful, you are prone to errors, especially when dealing with paths and formats. Just pay attention to the details, reading JSON files should be a relatively easy thing.
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