106 lines
1.7 KiB
Markdown
106 lines
1.7 KiB
Markdown
# JSON and dict
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{:.no_toc}
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<nav markdown="1" class="toc-class">
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* TOC
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{:toc}
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</nav>
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## The goal
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A combination of JSON (JavaScript Object Notation) file and dictionaries allows to organize parameters in an external file.
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Questions to [David Rotermund](mailto:davrot@uni-bremen.de)
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## [json -- JSON encoder and decoder](https://docs.python.org/3/library/json.html)
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### [dump](https://docs.python.org/3/library/json.html#json.dump)
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```python
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import json
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a = dict(one=1, two=2, three=3)
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with open("data_out.json", "w") as file:
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json.dump(a, file)
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```
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Content of data_out.json:
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```json
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{"one": 1, "two": 2, "three": 3}
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```
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### [load](https://docs.python.org/3/library/json.html#json.load)
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```python
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import json
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with open("data_out.json", "r") as file:
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b = json.load(file)
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print(b)
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```
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Output:
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```python
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{'one': 1, 'two': 2, 'three': 3}
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```
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## [jsmin](https://github.com/tikitu/jsmin/) and [loads](https://docs.python.org/3/library/json.html#json.loads)
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```shell
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pip install jsmin
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```
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Maybe you want to have comments in your config file.
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Content of data_in.json:
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```json
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// This an important comment...
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{
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"one": 1,
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"two": 2,
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"three": 3
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}
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```
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Note for **VS Code**: You need to change the filetype from **JSON** to **JSON with comments**. Lower right corner.
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The normal JSON functions fails:
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```python
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import json
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with open("data_in.json", "r") as file:
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b = json.load(file)
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print(b)
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```
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Output:
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```python
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JSONDecodeError: Expecting value: line 1 column 1 (char 0)
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```
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With jsmin:
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```python
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import json
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from jsmin import jsmin
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with open("data_in.json", "r") as file:
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minified = jsmin(file.read())
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b = json.loads(minified)
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print(b)
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```
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Output:
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```python
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{'one': 1, 'two': 2, 'three': 3}
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```
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