如何將矢量映射到R中的不同範圍？

Question

我在範圍[1,10]

c(1,2,9,10) 

一個載體，我想將它映射到一個不同的範圍，例如[12,102]

c(12,22,92,102) 

有R中已經做了這樣的功能？

Answer 1

linMap <- function(x, from, to) 
    (x - min(x))/max(x - min(x)) * (to - from) + from 

linMap(vec, 12, 102) 
# [1] 12 22 92 102 

或者更明確：用包scales

linMap <- function(x, from, to) { 
    # Shifting the vector so that min(x) == 0 
    x <- x - min(x) 
    # Scaling to the range of [0, 1] 
    x <- x/max(x) 
    # Scaling to the needed amplitude 
    x <- x * (to - from) 
    # Shifting to the needed level 
    x + from 
} 

rescale(vec, c(12, 102))作品。也可以按照@flodel的建議以巧妙的方式利用approxfun：

linMap <- function(x, a, b) approxfun(range(x), c(a, b))(x)