Extracting a Data Portion

{portion} is a small R package that helps to extract a data portion:

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

2. the relative portion size can be selected

3. allows to select first, last, random, similar or dissimilar data points

4. can portion either row- or column-wise

Installation

You can install the released version from CRAN with:

install.packages("portion")

Example

Can portion a vector:

portion(c(1:5, 51:55), proportion = 0.5, how = "similar")
#> [1] 51 52 53 54 55
#> attr(,"indices")
#> [1]  6  7  8  9 10
portion(1:10, proportion = 0.4, how = "dissimilar", centers = 4)
#> [1]  1  5  8 10
#> attr(,"indices")
#> [1]  1  5  8 10

Can portion a matrix:

portion(matrix(LETTERS[1:24], nrow = 4), proportion = 0.5, how = "first")
#>      [,1] [,2] [,3] [,4] [,5] [,6]
#> [1,] "A"  "E"  "I"  "M"  "Q"  "U" 
#> [2,] "B"  "F"  "J"  "N"  "R"  "V" 
#> attr(,"indices")
#> [1] 1 2
portion(matrix(LETTERS[1:24], nrow = 4), proportion = 0.5, how = "first", byrow = FALSE)
#>      [,1] [,2] [,3]
#> [1,] "A"  "E"  "I" 
#> [2,] "B"  "F"  "J" 
#> [3,] "C"  "G"  "K" 
#> [4,] "D"  "H"  "L" 
#> attr(,"indices")
#> [1] 1 2 3

Can portion a data.frame:

portion(as.data.frame(diag(8)), proportion = 0.3, how = "random")
#>   V1 V2 V3 V4 V5 V6 V7 V8
#> 3  0  0  1  0  0  0  0  0
#> 5  0  0  0  0  1  0  0  0
#> 6  0  0  0  0  0  1  0  0
portion(as.data.frame(diag(8)), proportion = 0.3, how = "random", byrow = FALSE)
#>   V1 V2 V5
#> 1  1  0  0
#> 2  0  1  0
#> 3  0  0  0
#> 4  0  0  0
#> 5  0  0  1
#> 6  0  0  0
#> 7  0  0  0
#> 8  0  0  0

Can work on a list:

portion(list(1:5, diag(3), data.frame(1:3, 2:4)), proportion = 0.5, how = "last")
#> [[1]]
#> [1] 3 4 5
#> attr(,"indices")
#> [1] 3 4 5
#> 
#> [[2]]
#>      [,1] [,2] [,3]
#> [1,]    0    1    0
#> [2,]    0    0    1
#> attr(,"indices")
#> [1] 2 3
#> 
#> [[3]]
#>   X1.3 X2.4
#> 2    2    3
#> 3    3    4