- Did you notice anything weird while finishing the Choice Operations exercise?
- Take a closer look at item 4.
Floating point
> x <- 1.3
> y <- 2.8
> x * 2 + 0.2 == y
[1] FALSE
> 1.3 * 2 + 0.2
[1] 2.8
- What’s going on?
- Unexpected result from computer arithmetic
- Numbers combine to include very small trailing digit
- See this more easily in Python
>>> 1.3 * 2 + 0.2 == 2.8
False
>>> 1.3 * 2 + 0.2
2.8000000000000003
Testing equality with decimals
round(x * 2 + 0.2, 1) == yall.equal(x * 2 + 0.2, y)