How To Convert Python Dictionary To JSON? (original) (raw)

Last Updated : 12 Jul, 2025

In Python, a dictionary stores information using key-value pairs. But if we want to save this data to a file, share it with others, or send it over the internet then we need to convert it into a format that computers can easily understand. JSON (JavaScript Object Notation) is a simple format used for this. **For example, if we have a dictionary d = {"name": "Tom", "age": 10, "city": "Paris"}, converting it to JSON will represent the data as {"name": "Tom", "age": 10, "city": "Paris"}. Although both look the same, if we check the type of the JSON data, it will be a string, not a dictionary.

Using json.dumps()

json.dumps() converts a dictionary into a JSON-formatted string. It allows various formatting options like indentation, sorting keys and ensuring ASCII encoding, making it useful for debugging and human-readable outputs.

Python `

import json

d = {"name": "shakshi", "age": 21}

print(json.dumps(d, indent=4)) # Pretty print JSON print(json.dumps(d, sort_keys=True)) # Sorted keys print(json.dumps(d, ensure_ascii=False)) # Non-ASCII encoding print(json.dumps([{k: d[k]} for k in d])) # Convert to JSON array format

`

Output

{ "name": "shakshi", "age": 21 } {"age": 21, "name": "shakshi"} {"name": "shakshi", "age": 21} [{"name": "shakshi"}, {"age": 21}]

**Explanation:

• **json.dumps(d, indent=4) converts the dictionary to a JSON-formatted string with 4-space indentation for readability.
• **json.dumps(d, sort_keys=True) converts the dictionary to a JSON string with keys sorted alphabetically.
• **json.dumps(d, ensure_ascii=False) converts the dictionary to a JSON string while preserving non-ASCII characters. If set to True (default), non-ASCII characters are escaped.
• **[{key: d[key]} for key in d] creates a list of dictionaries, each containing a single key-value pair from d.

**Note: For more information, refer to Read, Write, and Parse JSON using Python

Table of Content

• Using json.dump()
• Converting nested dictionary to json
• Difference Between Dictionary and JSON

Using json.dump()

json.dump() writes a dictionary directly into a file in JSON format. It avoids the need to manually open and write the JSON string to a file. Additional options like indentation and key sorting can be applied to make the output more structured. This method is best suited for persisting JSON data to a file.

Python `

import json

d = {"name": "Shakshi", "age": 21}

files = [ ("sample_default.json", {}), ("sample_pretty.json", {"indent": 4}), ("sample_sorted.json", {"sort_keys": True, "indent": 4}), ("sample_ascii.json", {"ensure_ascii": False, "indent": 4}), ]

for filename, options in files: with open(filename, "w") as f: json.dump(d, f, **options)

Print JSON representations for reference

for _, options in files: print(json.dumps(d, **options))

`

Output

{"name": "Shakshi", "age": 21} { "name": "Shakshi", "age": 21 } { "age": 21, "name": "Shakshi" } { "name": "Shakshi", "age": 21 }

**Explanation:

• **json.dump(d, outfile) writes the dictionary **d to a file sample_default.json in JSON format without formatting.
• **json.dump(d, outfile, indent=4) writes the dictionary **d to sample_pretty.json with 4-space indentation.
• **json.dump(d, outfile, sort_keys=True) writes **d to sample_sorted.json with keys sorted alphabetically.
• **json.dump(d, outfile, ensure_ascii=False) writes **d to sample_ascii.json, preserving non-ASCII characters.

Converting nested dictionary to json

Dictionaries can have **nested structures and json.dumps() effectively handles such cases. With indentation, nested objects remain easy to read, ensuring clarity in complex data structures. Encoding and sorting keys can also be applied to nested dictionaries, preserving the hierarchical structure.

Python `

import json

d = {"name": "shakshi", "age": 21, "address": {"city": "Delhi"}}

print(json.dumps(d, indent=4)) # Pretty print JSON print(json.dumps(d, sort_keys=True, indent=4)) # Sorted keys print(json.dumps(d, ensure_ascii=False, indent=4)) # Non-ASCII encoding print(json.dumps([{k: d[k]} for k in d], indent=4)) # Convert to JSON array format

`

**Output

<class 'str'> {
"name": "shakshi",
"age": 21,
"address": {
"city": "Delhi"
}
}
{
"address": {
"city": "Delhi"
},
"age": 21,
"name": "shakshi"
}
{
"name": "shakshi",
"age": 21,
"address": {
"city": "Delhi"
}
}
[
{
"name": "shakshi"
},
{
"age": 21
},
{
"address": {
"city": "Delhi"
}
}
]

**Explanation:

• **json.dumps(d, indent=4) converts the dictionary d into a JSON-formatted string and uses an indentation of 4 spaces for better readability.
• **json.dumps(d, sort_keys=True, indent=4) converts d into a JSON string with keys sorted in alphabetical order.
• **json.dumps(d, ensure_ascii=False, indent=4) converts d to a JSON string while preserving non-ASCII characters.
• **json.dumps([{key: d[key]} for key in d], indent=4) converts d into an array of dictionaries, each containing a single key-value pair.

Difference Between Dictionary and JSON