Aggregate - R Programming

aggregate computes summaries by group. Formula syntax names the value column and grouping column.

Program

Play the script to sum amounts by region and read the east total.

aggregate_summary.R

sales <- data.frame(region = c("east", "west", "east"), amount = c(10, 7, 5))
summary <- aggregate(amount ~ region, sales, sum)
east_total <- summary$amount[summary$region == "east"]
cat(east_total, "\n", sep = "")

aggregate `aggregate(amount ~ region, sales, sum)` groups by region and sums amounts.

formula `amount ~ region` reads as summarize amount by region.

grouped summary Grouped summaries reduce many rows to one row per group.