[, [[, and $ pull pieces.

Goal

Print Kisumu units two ways.

df <- data.frame(
  city = c("Nairobi", "Mombasa", "Kisumu"),
  units = c(12, 8, 5),
  stringsAsFactors = FALSE
)
print(df[df$city == "Kisumu", ])
print(df$units[3])

cities <- c("Nairobi", "Mombasa", "Kisumu")
print(cities[c(1, 3)])
print(cities[-2])

lst <- list(city = "Nakuru", units = 4)
print(lst[["city"]])
print(lst$units)

x <- 10:14
print(x[x >= 12])