Create a sequence from vectors with start and end positions

Question

Given two separate vectors of equal length: f.start and f.end, I would like to construct a sequence (by 1), going from f.start[1]:f.end[1] to f.start[2]:f

Answer 1

You can try using mapply or Map, which iterates simultaneously on your two vectors. You need to provide the function as first argument:

vec1 = c(1,33,50)
vec2 = c(10,34,56)

unlist(Map(':',vec1, vec2))
# [1]  1  2  3  4  5  6  7  8  9 10 33 34 50 51 52 53 54 55 56

Just replace vec1 and vec2 by f.start and f.end provided all(f.start<=f.end)