This function should only be used
within summarise(), mutate() and filter().
n()n() will only be evaluated inside a function call, where it
returns an integer.
ir <- as_iranges(
data.frame(start = 1:10,
width = 5,
name = c(rep("a", 5), rep("b", 3), rep("c", 2))
)
)
by_names <- group_by(ir, name)
summarise(by_names, n = n())
#> DataFrame with 3 rows and 2 columns
#> name n
#> <character> <integer>
#> 1 a 5
#> 2 b 3
#> 3 c 2
mutate(by_names, n = n())
#> IRanges object with 10 ranges and 2 metadata columns:
#> Groups: name [3]
#> start end width | name n
#> <integer> <integer> <integer> | <character> <integer>
#> [1] 1 5 5 | a 5
#> [2] 2 6 5 | a 5
#> [3] 3 7 5 | a 5
#> [4] 4 8 5 | a 5
#> [5] 5 9 5 | a 5
#> [6] 6 10 5 | b 3
#> [7] 7 11 5 | b 3
#> [8] 8 12 5 | b 3
#> [9] 9 13 5 | c 2
#> [10] 10 14 5 | c 2
filter(by_names, n() >= 3)
#> IRanges object with 8 ranges and 1 metadata column:
#> Groups: name [2]
#> start end width | name
#> <integer> <integer> <integer> | <character>
#> [1] 1 5 5 | a
#> [2] 2 6 5 | a
#> [3] 3 7 5 | a
#> [4] 4 8 5 | a
#> [5] 5 9 5 | a
#> [6] 6 10 5 | b
#> [7] 7 11 5 | b
#> [8] 8 12 5 | b