Centering and Scaling of Numeric Data

Provides simple methods for centering and scaling of numeric data. Columns or rows can be ignored when normalizing or be normalized jointly.

Normalization of Numeric Data

The {normalize} R package offers convenient tools to normalize numeric data from common R objects:

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")

Examples

Normalize a vector by centering, scaling, or both:

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

Normalize a matrix column-wise, optionally with joint centering:

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

Normalize a data.frame while keeping non-numeric columns unchanged:

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