I just encounter a very weird issue. Following is the code
a <- 90.8
b <- 90.6
a - b == 0.2
returns FALSE
Any ideas???
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2because of floating point. You can check `print(a-b, digits=20)# [1] 0.20000000000000284` – akrun Oct 05 '17 at 13:57
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Yeah, that's true. So how can I fix that? I need to write an if condition on the difference. – Arthur Oct 05 '17 at 13:59
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Well, what condition do you need? Presumably, it is not that the difference is exactly 0.2. – G5W Oct 05 '17 at 14:01
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2Use `all.equal`. – Taylor H Oct 05 '17 at 14:02
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What if I want to use inequality? For example, `90.8 - 90.6 <= 0.2`, which will give `FALSE` – Arthur Oct 05 '17 at 14:05
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1`is.less `. If you want equality use `abs(x - y) < tol`. – Rui Barradas Oct 05 '17 at 14:11
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@RuiBarradas Thank you! – Arthur Oct 05 '17 at 14:14
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1`isTRUE(all.equal(a - b, 0.2))` is what you should be using – rawr Oct 05 '17 at 14:26
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@rawr That's the standard way but the reason why the function in my comment is that `all.equal` is not vectorized and sometimes we need a logical vector. Note that I use the same default tolerance as `all.equal`. – Rui Barradas Oct 05 '17 at 17:37