Python: Round a Decimal value to the nearest multiple of 0.10, unless already an exact multiple of 0.05

Last update on April 02 2025 12:31:42 (UTC/GMT +8 hours)

3. Round to Nearest 0.10 (with 0.05 Exception)

Write a Python program to round a decimal value to the nearest multiple of 0.10, unless already an exact multiple of 0.05. Use decimal.Decimal

Sample Solution:

Python Code:

from decimal import Decimal
#Source: https://bit.ly/3hEyyY4

def round_to_10_cents(x):
    remainder = x.remainder_near(Decimal('0.10'))
    if abs(remainder) == Decimal('0.05'):
        return x
    else:
        return x - remainder

# Test code.
for x in range(80, 120):
    y = Decimal(x) / Decimal('1E2')
    print("{0} rounds to {1}".format(y, round_to_10_cents(y)))

Sample Output:

0.80 rounds to 0.80
0.81 rounds to 0.80
0.82 rounds to 0.80
0.83 rounds to 0.80
0.84 rounds to 0.80
0.85 rounds to 0.85
0.86 rounds to 0.90
0.87 rounds to 0.90
0.88 rounds to 0.90
0.89 rounds to 0.90
0.90 rounds to 0.90
0.91 rounds to 0.90
0.92 rounds to 0.90
0.93 rounds to 0.90
0.94 rounds to 0.90
0.95 rounds to 0.95
0.96 rounds to 1.00
0.97 rounds to 1.00
0.98 rounds to 1.00
0.99 rounds to 1.00
1.00 rounds to 1.00
1.01 rounds to 1.00
1.02 rounds to 1.00
1.03 rounds to 1.00
1.04 rounds to 1.00
1.05 rounds to 1.05
1.06 rounds to 1.10
1.07 rounds to 1.10
1.08 rounds to 1.10
1.09 rounds to 1.10
1.10 rounds to 1.10
1.11 rounds to 1.10
1.12 rounds to 1.10
1.13 rounds to 1.10
1.14 rounds to 1.10
1.15 rounds to 1.15
1.16 rounds to 1.20
1.17 rounds to 1.20
1.18 rounds to 1.20
1.19 rounds to 1.20

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to round a Decimal value to the nearest 0.10, but if it’s already an exact multiple of 0.05, leave it unchanged, and print the result.
• Write a Python function that accepts a Decimal and returns it rounded to the nearest 0.10 unless it is an exact multiple of 0.05, then test it on a range of values.
• Write a Python script to demonstrate the rounding behavior by converting a list of Decimal values according to the nearest 0.10 rule with the 0.05 exception.
• Write a Python program to compare two Decimal values: one rounded to the nearest 0.10 and one rounded to the nearest 0.05, then print the differences.

Python Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a Python program to configure the rounding to round up and round down a given decimal value.
Next: Write a Python program to configure the rounding to round to the floor, ceiling.