How Can I Serialize Decimal Objects to JSON in Python While Preserving Precision?

Serializing Decimal Objects to JSON in Python

A common issue arises when attempting to encode a Decimal object into a JSON string, preserving its precision. The default approach of converting to a float results in loss of precision.

Solution 1: SimpleJSON (Python 2.1 and above)

SimpleJSON provides intuitive support for Decimal objects through its 'use_decimal' flag:

import simplejson as json

json.dumps(Decimal('3.9'), use_decimal=True)
# Output: '3.9'

By default, 'use_decimal' is set to True, eliminating the need for explicit specification:

json.dumps(Decimal('3.9'))
# Output: '3.9'

Solution 2: Custom JSON Encoder

If SimpleJSON is not an option, you can create a custom JSON encoder that handles Decimal objects:

import decimal
import json

class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, decimal.Decimal):
            return float(obj)
        # Handle other object types as needed
        return super().default(obj)

json.dumps(Decimal('3.9'), cls=DecimalEncoder)
# Output: '3.8999999999999999'

Note that this approach will convert the Decimal object to a float, potentially causing precision loss.

The above is the detailed content of How Can I Serialize Decimal Objects to JSON in Python While Preserving Precision?. For more information, please follow other related articles on the PHP Chinese website!