Determine precision and scale of particular number in Python

Question

I have a variable in Python containing a floating point number (e.g. num = 24654.123), and I\'d like to determine the number\'s precision and scale values (in t

Answer 1

Not possible with floating point variables. For example, typing

>>> 10.2345

gives:

10.234500000000001

So, to get 6,4 out of this, you will have to find a way to distinguish between a user entering 10.2345 and 10.234500000000001, which is impossible using floats. This has to do with the way floating point numbers are stored. Use decimal.

import decimal
a = decimal.Decimal('10.234539048538495')
>>> str(a)
'10.234539048538495'
>>>  (len(str(a))-1, len(str(a).split('.')[1]))
(17,15)