Find nearest smaller number

Question

I have a vector of numbers

f <- c(1, 3, 5, 8, 10, 12, 19, 27)

I want to compare the values in the vector to another number, and find the c

Answer 1

You could try:

x <- 18
f <- c(1,3,6,8,10,12,19,27)

ifelse(x %in% f, which(f %in% x), which.min(abs(f - x)) - 1)

That way if x is not in f, it will return the nearest previous index. If x is in f, it will return x index.