Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

library(dplyr)
library(tidyr)

sales <- data.frame(
    month  = rep(c("Jan","Feb","Mar","Apr"), times = 2),
    region = rep(c("North","South"), each = 4),
    revenue = c(120,135,110,150, 90,95,105,115)
)

# Window functions inside mutate after group_by
sales |>
    group_by(region) |>
    mutate(
        rank_rev    = row_number(desc(revenue)),
        pct_of_max  = revenue / max(revenue),
        cumulative  = cumsum(revenue),
        mom_change  = revenue - lag(revenue, default = first(revenue))
    ) |>
    ungroup()

# rowwise() for row-level computation
scores <- data.frame(
    student = c("Alice","Bob","Carol"),
    math    = c(88, 72, 95),
    english = c(91, 85, 78),
    science = c(79, 90, 88)
)
scores |>
    rowwise() |>
    mutate(
        avg_score = mean(c_across(math:science)),
        max_score = max(c_across(math:science))
    ) |>
    ungroup()

# pivot_longer — wide to long
long_sales <- sales |>
    rename(rev = revenue) |>
    pivot_longer(cols = rev, names_to = "metric", values_to = "value")

# More typical pivot_longer: multiple measure columns
scores_long <- scores |>
    pivot_longer(cols      = -student,
                 names_to  = "subject",
                 values_to = "score")
scores_long

# pivot_wider — long back to wide
scores_long |>
    pivot_wider(names_from  = subject,
                values_from = score)

# separate and unite
data.frame(date_range = c("2024-01-01/2024-03-31",
                           "2024-04-01/2024-06-30")) |>
    separate(date_range, into = c("start", "end"), sep = "/")

scores |>
    unite("id", student, sep = "_") |>
    head(2)