Have you performed simple arithmetic operations like 0.1 + 0.2? You might have gotten something strange: 0.1 + 0.2 = 0.30000000000000004.
Have you performed simple arithmetic operations like 0.1 + 0.2? You might have gotten something strange: 0.1 + 0.2 = 0.30000000000000004.
A good way to think of it is to compare something similar in decimal. .1 and .2 are precise values in decimal, but can’t be represented as perfectly in binary. 1/3 might be a pretty good similar-enough example. With a lack of precision, that might become 0.33333333, which when added in the expression 1/3 + 1/3 + 1/3 will give you 0.99999999, instead of the correct answer of 1.
Python has no issues representing
1/3 + 1/3 + 1/3as 1. I just opened a python interpreter, imported absolutely no libraries and typed
1/3 + 1/3 + 1/3enter and got 1 as the result. Seems like if python could do that, JavaScript should be able to as well.Now try opening js interpreter and doing the same.
Also, try
0.1+0.2in python interpreter.I’ll pass on the js interpreter. I don’t feel like learning the arcane runes.
To your point, Python handles those by giving you 0.300000004 might have missed a zero but valid point nonetheless
I thought it was a rather simple analogue, but I guess it was too complicated for some?
I said nothing about JavaScript or Python or any other language with my 1/3 example. I wasn’t even talking about binary. It was an example of something that might be problematic if you added numbers in an imprecise way in decimal, the same way binary floating point fails to accurately represent 1/10 + 1/5 from the OP.
That’s because the nearest representable float to 0.99999999999999 is 1.0 - not because Python is handling rationals correctly.
This is a float imprecision issue that just happens to work out in this case.
It’s worth wondering why, if Python is OK with “/“ producing a result of a different type than its arguments, don’t they implement a ratio type. e.g. https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node18.html#SECTION00612000000000000000