Split Around First Predicate Flip

Splits a sequence into left context, matched element, and right context at the first point where `predicate` becomes `TRUE` on accumulated monoid measures.

Usage

split_around_by_predicate(t, predicate, monoid_name, accumulator = NULL)

Arguments

t

A `flexseq`.

predicate

Function on accumulated measure values.

monoid_name

Name of monoid from `attr(t, "monoids")`.

accumulator

Optional starting measure (defaults to monoid identity).

Value

A list with `left`, `elem`, and `right`.

Examples

x <- as_flexseq(letters[1:6])
x
#> FingerTree <size=6, named=no>
#>   monoids: none
#> 
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b"
#> 
#> [[3]]
#> [1] "c"
#> 
#> [[4]]
#> [1] "d"
#> 
#> [[5]]
#> [1] "e"
#> 
#> [[6]]
#> [1] "f"
#> 

s <- split_around_by_predicate(x, function(v) v >= 4, ".size")
s$elem
#> [1] "d"
s$left
#> FingerTree <size=3, named=no>
#>   monoids: none
#> 
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b"
#> 
#> [[3]]
#> [1] "c"
#> 
s$right
#> FingerTree <size=2, named=no>
#>   monoids: none
#> 
#> [[1]]
#> [1] "e"
#> 
#> [[2]]
#> [1] "f"
#>