如何将矢量映射到R中的不同范围？

Question

我在范围[1,10]

c(1,2,9,10) 

一个载体，我想将它映射到一个不同的范围，例如[12,102]

c(12,22,92,102) 

有R中已经做了这样的功能？

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 

或者更明确：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的建议以巧妙的方式利用approxfun：

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