Count pairs of items within a group

Count the number of times each pair of items appear together within a group defined by "feature." For example, this could count the number of times two words appear within documents).

Usage

pairwise_count(tbl, item, feature, wt = NULL, ...)

pairwise_count_(tbl, item, feature, wt = NULL, ...)

Arguments

tbl

Table

item

Item to count pairs of; will end up in item1 and item2 columns

feature

Column within which to count pairs item2 columns

wt

Optionally a weight column, which should have a consistent weight for each feature

...

Extra arguments passed on to squarely, such as diag, upper, and sort

See also

squarely()

Examples

library(dplyr)
dat <- tibble(group = rep(1:5, each = 2),
              letter = c("a", "b",
                         "a", "c",
                         "a", "c",
                         "b", "e",
                         "b", "f"))

# count the number of times two letters appear together
pairwise_count(dat, letter, group)
#> # A tibble: 8 × 3
#>   item1 item2     n
#>   <chr> <chr> <dbl>
#> 1 b     a         1
#> 2 c     a         2
#> 3 a     b         1
#> 4 e     b         1
#> 5 f     b         1
#> 6 a     c         2
#> 7 b     e         1
#> 8 b     f         1
pairwise_count(dat, letter, group, sort = TRUE)
#> # A tibble: 8 × 3
#>   item1 item2     n
#>   <chr> <chr> <dbl>
#> 1 c     a         2
#> 2 a     c         2
#> 3 b     a         1
#> 4 a     b         1
#> 5 e     b         1
#> 6 f     b         1
#> 7 b     e         1
#> 8 b     f         1
pairwise_count(dat, letter, group, sort = TRUE, diag = TRUE)
#> # A tibble: 13 × 3
#>    item1 item2     n
#>    <chr> <chr> <dbl>
#>  1 a     a         3
#>  2 b     b         3
#>  3 c     a         2
#>  4 a     c         2
#>  5 c     c         2
#>  6 b     a         1
#>  7 a     b         1
#>  8 e     b         1
#>  9 f     b         1
#> 10 b     e         1
#> 11 e     e         1
#> 12 b     f         1
#> 13 f     f         1