test <- c(2,3,4,6)         ## 测试数据

a <- scale(test,center = F, scale = F)   ## 既不中心化， 也不标准化
a

b <- scale(test, center = T, scale = F)   ## 中心化， 但是不标准化
b
b_test = test - mean(test)   ##中心化， 减去平均值进行验证
b_test

c <- scale(test, center = F, scale = T)    ## 标准化， 但不中心化
c
c_test <- test/sqrt(sum(test^2)/(length(test) - 1))   ##标准化， 除以根方差验证
c_test

d <- scale(test, center = T, scale = T)       ## 即中心化， 又标准化
d
d_temp <- test - mean(test)                   ## 中心化， 减去平均值
d_test <- d_temp/sqrt(sum(d_temp^2)/(length(d_temp) - 1))   ## 标准化，除以根方差 
d_test

> test <- c(2,3,4,6)
> a <- scale(test,center = F, scale = F)
> a        ## a没有变化
     [,1]
[1,]    2
[2,]    3
[3,]    4
[4,]    6
> b <- scale(test, center = T, scale = F)   ## 中心化
> b
      [,1]
[1,] -1.75
[2,] -0.75
[3,]  0.25
[4,]  2.25
attr(,"scaled:center")
[1] 3.75
> b_test = test - mean(test)   ## 减去平均值验证
> b_test
[1] -1.75 -0.75  0.25  2.25
> c <- scale(test, center = F, scale = T)   ## 标准化
> c
          [,1]
[1,] 0.4296689
[2,] 0.6445034
[3,] 0.8593378
[4,] 1.2890068
attr(,"scaled:scale")
[1] 4.654747
> c_test <- test/sqrt(sum(test^2)/(length(test) - 1))   ## 标准化，除以根方差验证
> c_test
[1] 0.4296689 0.6445034 0.8593378 1.2890068
> d <- scale(test, center = T, scale = T)    ## 即中心化， 又标准化
> d
          [,1]
[1,] -1.024695
[2,] -0.439155
[3,]  0.146385
[4,]  1.317465
attr(,"scaled:center")
[1] 3.75
attr(,"scaled:scale")
[1] 1.707825
> d_temp <- test - mean(test)    ## 中心化
> d_test <- d_temp/sqrt(sum(d_temp^2)/(length(d_temp) - 1))   ## 除以根方差，标准化
> d_test
[1] -1.024695 -0.439155  0.146385  1.317465