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Create a categorical similarity matrix

Source: R/same_category.R
same_category.Rd

same_category() takes a factor vector and returns a pairwise similarity matrix indicating whether observations belong to the same category.

Usage

same_category(x)

Arguments

x

A factor vector.

Value

A numeric matrix with one row and one column for each element of x. If x has names, they are used as row and column names.

Details

The returned matrix contains:

  • 1 when two observations are in the same category

  • 0 when two observations are in different categories

  • NA when either observation has a missing value

See also

dist_category()

Examples

group <- factor(c("A", "A", "B", "C"))

same_category(group)
#>      [,1] [,2] [,3] [,4]
#> [1,]    1    1    0    0
#> [2,]    1    1    0    0
#> [3,]    0    0    1    0
#> [4,]    0    0    0    1

# Named input preserves names in the output matrix
named_group <- factor(c("red", "blue", "red"))
names(named_group) <- c("sample1", "sample2", "sample3")

same_category(named_group)
#>         sample1 sample2 sample3
#> sample1       1       0       1
#> sample2       0       1       0
#> sample3       1       0       1

# Missing values return NA for comparisons involving the missing value
group_with_na <- factor(c("A", NA, "B"))
same_category(group_with_na)
#>      [,1] [,2] [,3]
#> [1,]    1   NA    0
#> [2,]   NA   NA   NA
#> [3,]    0   NA    1