R中的向量列表上的foreach

Question

I have a list like this

list1<- list(c(12,45,12,0,0),c(12,45,12,0,1),c(14,45,12,0,2),c(12,15,12,0,3),c(12,45,17,0,4))

I want to iterate through this list by using foreach in R. The goal here is to compare a random vector like c(1,1,2,0,6) with these vectors in the list. By "compare", I mean I need to calculate the euclidean distance between these vectors and find the closest one to my random vector.

Answer 1

The most efficient approach to calculate the distances could be achieved with the dist function.

# a random vector
rvec  <- c(1,1,2,0,6)

# a list of coordinates
list1 <- list(c(12,45,12,0,0),
              c(12,45,12,0,1),
              c(14,45,12,0,2),
              c(12,15,12,0,3),
              c(12,45,17,0,4))

# calculate distances between the random vector and the list elements:
dist(rbind(rvec, t(matrix(unlist(list1), length(list1)))))[seq_along(list1)]

[1] 46.82948 46.71188 47.12749 20.63977 47.81213