在 R 中将数字四舍五入到最接近的值（具有不同的间隔）

Question

I want to round (or replace) numbers in a

a <- c(0.505, 1.555, 2.667, 53.850, 411.793)

to the nearest values in b :

b <- c(0, 5, 10, 50, 100, 200, 500)

The output will be this:

a_rnd <- c(0, 0, 5, 50, 500)

The logic is simple but I couldn't find any solution, because all the approaches I found require values in b have an equal interval!

How can I achieve this?

Answer 1

You can use sapply to loop over all values of a and use these indexes to extract the proper b values

b[sapply(a, function(x) which.min(abs(x - b)))]
#> [1]   0   0   5  50 500

Answer 2

This is a relatively simple approach:

b[apply(abs(outer(a, b, "-")), 1, which.min)]