Centering and Scaling of Numeric Data.

Normalization of Numeric Data

{normalize} is a small R package that allows for normalization (i.e., centering to zero mean and scaling to unit variance) of numeric data. The goal is to extend the base R scale() function with some additional features:

1. works for vector, matrix, data.frame, and list objects

2. can normalize by row or by column

3. can ignore some rows or columns when normalizing

4. allows for joint normalizing of certain rows or columns

Installation

You can install the released version from CRAN with:

install.packages("normalize")

Example

Can normalize a vector:

normalize(1:10)
#>  [1] -1.4863011 -1.1560120 -0.8257228 -0.4954337 -0.1651446  0.1651446
#>  [7]  0.4954337  0.8257228  1.1560120  1.4863011
#> attr(,"center")
#> [1] 5.5
#> attr(,"scale")
#> [1] 3.02765
normalize(1:10, center = FALSE)
#>  [1] 0.3302891 0.6605783 0.9908674 1.3211565 1.6514456 1.9817348 2.3120239
#>  [8] 2.6423130 2.9726022 3.3028913
#> attr(,"scale")
#> [1] 3.02765
normalize(1:10, scale = FALSE)
#>  [1] -4.5 -3.5 -2.5 -1.5 -0.5  0.5  1.5  2.5  3.5  4.5
#> attr(,"center")
#> [1] 5.5

Can normalize a matrix:

normalize(
  matrix(1:12, nrow = 3, ncol = 4),
  jointly = list(1:2, 3:4) # joint normalization of columns 1, 2 and 3, 4
)
#>      [,1] [,2] [,3] [,4]
#> [1,] -2.5  0.5 -2.5  0.5
#> [2,] -1.5  1.5 -1.5  1.5
#> [3,] -0.5  2.5 -0.5  2.5
#> attr(,"center")
#> [1] 3.5 3.5 9.5 9.5
#> attr(,"scale")
#> [1] 1 1 1 1

Can normalize a data.frame:

normalize(
  data.frame(a = 1:3, b = c("A", "B", "C"), c = 7:9, d = 10:12),
  ignore = 2 # ignore character column 2 for normalization
)
#>    a b  c  d
#> 1 -1 A -1 -1
#> 2  0 B  0  0
#> 3  1 C  1  1

Can work on a list:

normalize(list(1:5, diag(3), data.frame(1:3, 2:4)))
#> [[1]]
#> [1] -1.2649111 -0.6324555  0.0000000  0.6324555  1.2649111
#> attr(,"center")
#> [1] 3
#> attr(,"scale")
#> [1] 1.581139
#> 
#> [[2]]
#>            [,1]       [,2]       [,3]
#> [1,]  1.1547005 -0.5773503 -0.5773503
#> [2,] -0.5773503  1.1547005 -0.5773503
#> [3,] -0.5773503 -0.5773503  1.1547005
#> attr(,"center")
#> [1] 0.3333333 0.3333333 0.3333333
#> attr(,"scale")
#> [1] 0.5773503 0.5773503 0.5773503
#> 
#> [[3]]
#>   X1.3 X2.4
#> 1   -1   -1
#> 2    0    0
#> 3    1    1