CODEWITHSUNDEEP
pythontypesprecision
kravemir
kravemir

Reputation: 11016

Double precision floating values in Python?

Are there data types with better precision than float?

Upvotes: 141

Views: 554427

Answers (5)

Fred Foo
Fred Foo

Reputation: 363607

Python's built-in float type has double precision (it's a C double in CPython, a Java double in Jython). If you need more precision, get NumPy and use its numpy.float128.

Upvotes: 191

Bittikettu
Bittikettu

Reputation: 29

Here is my solution. I first create random numbers with random.uniform, format them in to string with double precision and then convert them back to float. You can adjust the precision by changing '.2f' to '.3f' etc..

import random
from decimal import Decimal

GndSpeedHigh = float(format(Decimal(random.uniform(5, 25)), '.2f'))
GndSpeedLow = float(format(Decimal(random.uniform(2, GndSpeedHigh)), '.2f'))
GndSpeedMean = float(Decimal(format(GndSpeedHigh + GndSpeedLow) / 2, '.2f')))
print(GndSpeedMean)

Upvotes: -3

Gareth Rees
Gareth Rees

Reputation: 65854

For some applications you can use Fraction instead of floating-point numbers.

>>> from fractions import Fraction
>>> Fraction(1, 3**54)
Fraction(1, 58149737003040059690390169)

(For other applications, there's decimal, as suggested out by the other responses.)

Upvotes: 23

jerboa
jerboa

Reputation: 1421

May be you need Decimal

>>> from decimal import Decimal    
>>> Decimal(2.675)
Decimal('2.67499999999999982236431605997495353221893310546875')

Floating Point Arithmetic

Upvotes: 21

Jacob
Jacob

Reputation: 43229

Decimal datatype

  • Unlike hardware based binary floating point, the decimal module has a user alterable precision (defaulting to 28 places) which can be as large as needed for a given problem.

If you are pressed by performance issuses, have a look at GMPY

Upvotes: 74

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