Centering and Scaling of Numeric Data.

Normalization of Numeric Data

The {normalize}R package offers convenient tools to normalize (centering to zero mean and scaling to unit variance) numeric data:

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

2. can normalize by row or by column

3. can ignore rows or columns when normalizing

4. allows for joint normalizing of rows or columns

5. provides the normalizing constants as attributes

6. preserves object attributes

Installation

You can install the released version from CRAN with:

install.packages("normalize")

Example

Can normalize a vector:

x <- 1:10
normalize(x)
#>  [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(x, 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(x, 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