Find index of value in a sorted vector in R

Question

I have an ordered vector of unique integers in R and I want to find the index of the element closest to but less than or equal to some value. For example, for the vector

Answer 1

Base R provides findInterval which implements a binary search:

findInterval(17, c(4, 8, 15, 16, 23, 42))

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@Khashaa already mentioned this in a comment.