Formatting JSON output

Let’s say we have the following data:

>>> data = {"cats": [{"name": "Tubbs", "color": "white"}, {"name": "Pepper", "color": "black"}]}

Just dumping this as JSON does not do anything special here:

>>> print(json.dumps(data))
{"cats": [{"name": "Tubbs", "color": "white"}, {"name": "Pepper", "color": "black"}]}

Setting indentation to get prettier output

If we want pretty printing, we can set an indent size:

>>> print(json.dumps(data, indent=2))
{
  "cats": [{
  "cats": [
		{
			“name”: “Tubbs”,
			“color”: “white”
		},
		{
			“name”: “Pepper”,
			“color”: “black”
		}
	]
}

Sorting keys alphabetically to get consistent output

By default the order of keys in the output is undefined. We can get them in alphabetical order to make sure we always get the same output:

>>> print(json.dumps(data, sort_keys=True))
{"cats": [{"color": "white", "name": "Tubbs"}, {"color": "black", "name": "Pepper"}]}

Getting rid of whitespace to get compact output

We might want to get rid of the unnecessary spaces, which is done by setting separator strings different from the default ', ' and ': ':

>>>print(json.dumps(data, separators=(',', ':')))
{"cats":[{"name":"Tubbs","color":"white"},{"name":"Pepper","color":"black"}]}

Found a mistake? Have a question or improvement idea? Let me know.

Table Of Contents