What does the period mean in this code

[RodDog]

Sorry for the simple question. I just been researching this for too long and figured I'd ask. What does the period mean in this first bit of code. And does it mean the same thing in the second bit of code

car_data <- 
  mtcars %>%
  subset(hp > 100) %>%
  aggregate(. ~ cyl, data = ., FUN = . %>% mean %>% round(2)) %>%
  transform(kpl = mpg %>% multiply_by(0.4251)) %>%
  print

Same functioning as the period used in this code?

rnorm(1000)    %>%
multiply_by(5) %>%
add(5)         %>%
{ 
   cat("Mean:", mean(.), 
       "Variance:", var(.), "\n")
   head(.)
}

[technocrat]

This is an abbreviation for what is received from the %>% pipe. With the standard pipe |> the equivalent is [sort of] [|> some_function(x = _) but some functions work without it.

Works the same way in second, but again, only with the {magrittr} pipe version.

[RodDog]

Thank you for your time in providing this explanation.