Functional Programming Patterns

Reduce Total

Accumulate Values

Reduction combines many values into one result by repeatedly applying a combining function.

Program

Play the script to change the starting value for the accumulation.

reduce_total.R 
start <- 
values <- c(1, 2, 3)
total <- Reduce(`+`, values, init = start)
label <- paste("total", total, sep = ":")
cat(label, "\n", sep = "")

start <- 
values <- c(1, 2, 3)
total <- Reduce(`+`, values, init = start)
label <- paste("total", total, sep = ":")
cat(label, "\n", sep = "")

start <- 
values <- c(1, 2, 3)
total <- Reduce(`+`, values, init = start)
label <- paste("total", total, sep = ":")
cat(label, "\n", sep = "")
initial value `init` gives the reduction a starting accumulator.
combine `+` combines the accumulator with each value.
reduce `Reduce` returns one accumulated result.