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

Another one:

which.min(abs(18 - replace(f, f>18, Inf)))
#[1] 6

f[which.min(abs(18 - replace(f, f>18, Inf)))]
#[1] 12

Or as a function:

minsmaller <- function(x,value) which.min(abs(value - replace(x, x>value, Inf)))
minsmaller(f, 18)
#[1] 6
minsmaller(f, 19)
#[1] 7