JSON processing in Python: Difference between revisions

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Line 7: Line 7:
=Overview=
=Overview=
=Serialization=
=Serialization=
Serialization into a string:
<syntaxhighlight lang='python'>
<syntaxhighlight lang='python'>
import json
import json
 
d = ... # data structure
data = ...
s = json.dumps(d, indent=4, sort_keys=True)
with open("data_file.json", "w") as f:
    json.dump(data, f)
</syntaxhighlight>
</syntaxhighlight>
At stdout
There are situations when instances in the data structure are not serializable:
<font size=-1>
TypeError: Object of type datetime is not JSON serializable
</font>
In this case, use:
<syntaxhighlight lang='python'>
<syntaxhighlight lang='python'>
import json
s = json.dumps(d, indent=4, sort_keys=True, default=str)
</syntaxhighlight>


data = ...
Serialization into a file:
with open("/dev/stdout", "w") as f:
<syntaxhighlight lang='python'>
with open("data_file.json", "w") as f:
     json.dump(data, f)
     json.dump(data, f)
</syntaxhighlight>
</syntaxhighlight>
Line 32: Line 37:
print(data.get("size")) # displays 10
print(data.get("size")) # displays 10
print(data["details"]["shape"]["texture"]) # displays bumpy
print(data["details"]["shape"]["texture"]) # displays bumpy
</syntaxhighlight>
From file:
<syntaxhighlight lang='python'>
import json
filename = 'somefile.json'
with open(filename, 'rt') as f:
  ds = json.load(f)
</syntaxhighlight>
</syntaxhighlight>



Latest revision as of 02:55, 13 March 2022

External

Internal

Overview

Serialization

Serialization into a string:

import json
d = ... # data structure
s = json.dumps(d, indent=4, sort_keys=True)

There are situations when instances in the data structure are not serializable:

TypeError: Object of type datetime is not JSON serializable

In this case, use:

s = json.dumps(d, indent=4, sort_keys=True, default=str)

Serialization into a file:

with open("data_file.json", "w") as f:
    json.dump(data, f)

Deserialization

import json

data = json.loads('{"color":"blue", "size":10, "details":{"shape":{"texture":"bumpy", "orientation":"vertical"}}}')
print(data.get("color")) # displays blue
print(data["color"]) # displays blue
print(data.get("size")) # displays 10
print(data["details"]["shape"]["texture"]) # displays bumpy

From file:

import json

filename = 'somefile.json'
with open(filename, 'rt') as f:
  ds = json.load(f)

Safely Navigate a Complex Data Structure

Suggestions on how to safely recursively navigate a complex data structure:

Safely Navigate a Complex Data Structure