# How to Use the Decimal quantize() Method in Python

09/18/2021

Contents

In this article, you will learn how to use the Decimal quantize() method in Python.

## Decimal quantize() Method

The quantize() method in Python’s decimal module is used to round decimal numbers to a specified precision. This method is particularly useful when dealing with financial or monetary data where precision is important.

Here’s an example of how to use the quantize() method:

``````import decimal

# create a Decimal object
x = decimal.Decimal('10.34567')

# specify the precision to which you want to round the number
precision = decimal.Decimal('0.01')

# round the number using the quantize() method
rounded_number = x.quantize(precision)

print(rounded_number)
``````

In this example, we first import the decimal module and create a Decimal object called x with a value of 10.34567. We then create another Decimal object called precision with a value of 0.01, which specifies that we want to round to two decimal places.

Finally, we use the quantize() method on the x object, passing in the precision object as an argument. The result is a new Decimal object called rounded_number with a value of 10.35 (since 10.34567 rounds up to 10.35 when rounded to two decimal places).

You can also specify rounding modes other than the default rounding to nearest, such as rounding up, rounding down, and rounding towards zero. To do this, you can pass a decimal.Context object to the quantize() method with the desired rounding mode. Here’s an example:

``````import decimal

# create a Decimal object
x = decimal.Decimal('10.34567')

# specify the precision and rounding mode
context = decimal.Context(prec=4, rounding=decimal.ROUND_DOWN)
precision = decimal.Decimal('0.01')

# round the number using the quantize() method with the specified context
rounded_number = x.quantize(precision, context=context)

print(rounded_number)
``````

In this example, we create a decimal.Context object with a precision of 4 and a rounding mode of rounding down. We then pass this object as an argument to the quantize() method along with the precision object. The result is a new Decimal object called rounded_number with a value of 10.34 (since 10.34567 rounds down to 10.34 when rounded to two decimal places using the specified rounding mode).