This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 3 years ago.
Why is 100./3. = 33.333333333333336 and NOT 33.333333333333333 OR 33.333333333333334 ?
>>> a = 100./3.
>>> a
33.333333333333336
>>> b = a + a + a
>>> b
100.0
the wrong digit at the end is because of imprecision in representing the decimal as binary data in the interpreter; the interpreter is usually good at correcting those wrong-digits
Related
This question already has answers here:
Limiting floats to two decimal points
(35 answers)
how to format float number in python? [duplicate]
(3 answers)
variable number of digit in format string
(3 answers)
Closed 1 year ago.
I'm reading this textbook called "Practical Statistics for Data Scientists" and this :.3f keeps getting used in almost every f-string. What does :.3f mean? My guess is it has something to do with floating point numbers.
Example:
{house_lm_factor.intercept_:.3f}
This is show you how many number are printing:
>>> import math
>>> flt = math.pi
>>> f'{flt:.3f}'
'3.142'
>>> f'{flt:.5f}'
'3.14159'
>>> f'{flt:.10f}'
'3.1415926536'
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 1 year ago.
>>> import math
>>> math.sin(math.radians(180))
1.2246467991473532e-16
>>>
Isn't the sine of 180ยบ 0.0?
It is an approximation of pi. You can round it to 0.
This question already has answers here:
Is floating point math broken?
(31 answers)
Is floating point arbitrary precision available?
(5 answers)
Closed 3 years ago.
I have two numbers a and b:
a = 1562239482.739072
b = 1562239482.739071
If I perform a-b in python, I get 1.1920928955078125e-06. However, I want 0.000001, which is the right answer after subtraction.
Any help would be appreciated. Thank you in advance.
t = float(1562239482.739071)
T = float(1562239482.739072)
D = float(T - t)
print(float(D))
OR
t = 1562239482.739071
T = 1562239482.739072
D = T - t
print (D)
I get the same answer 1.1920928955078125e-06 using both as mentioned above. However, I want the result 0.000001.
Expected Result: 0.000001
Result : 1.1920928955078125e-06
This is common problem with floating point arithmetic. Use the decimal module
you can use Decimal like
from decimal import Decimal
a=Decimal('1562239482.739071')
b=Decimal('1562239482.739072')
c= b - a
print(c)
That will be the answer you want
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 6 years ago.
Using Python 2.7. Here is the code and output, my purpose is simply to check if a number is a cube number.
Source code,
x = 1728 ** (1.0/3)
print x
y = int(x)
print y
Output,
12.0
11
Because you're using floating points, and the result is some very very small fraction less than 12, and when you cast x to an int, the entire decimal portion of the number is discarded.
If what you want to do is round the number, use round().
This question already has answers here:
Limiting floats to two decimal points
(35 answers)
Closed 6 years ago.
I am aware of floating point being inaccurate and would like to know the best way to get 0.08354 instead of (0.08353999999999999) when I do the following in Python:
d = 8.354/100
print (d)
If you want absolute precision, use Decimals:
>>> import decimal
>>> decimal.Decimal('8.354') / 10
Decimal('0.8354')
Use the builtin round() function:
>>> d = 8.354/100
>>> d
0.08353999999999999
>>> round(d, 6)
0.08354
>>>