Fix float precision with decimal numbers

Question

a = 1

for x in range(5):
    a += 0.1
    print(a)

This is the result:

1.1
1.2000000000000002
1.3000000000000003
1.4000000000000004
1.         


        

Answer 1

Formatted output has been duly suggested by @Jaco. However, if you want control of precision in your variable beyond pure output, you might want to look at the decimal module.

from decimal import Decimal

a = 1
for x in range(3):
    a += Decimal('0.10')  # use string, not float as argument
    # a += Decimal('0.1000')
    print(a)  # a is now a Decimal, not a float

> 1.10  # 1.1000
> 1.20  # 1.2000
> 1.30  # 1.3000