Construct a Measure Monoid Specification

Construct a Measure Monoid Specification

Usage

measure_monoid(f, i, measure)

Arguments

f

Associative binary function over measure values.

i

Identity measure value for `f`.

measure

Function mapping a raw element to a measure value.

Value

An object of class `measure_monoid`.

Examples

sum_m <- measure_monoid(`+`, 0, as.numeric)
x <- as_flexseq(1:5)
x2 <- add_monoids(x, list(sum = sum_m))
attr(x2, "measures")$sum
#> [1] 15

# create a second monoid and add it to a sequence
nchar_sum <- measure_monoid(`+`, 0, function(el) nchar(as.character(el)))
x2 <- as_flexseq(letters[1:3])
x3 <- add_monoids(x2, list(nchar_sum = nchar_sum))
attr(x3, "measures")$nchar_sum
#> [1] 3