3.14 Pipes: Exposition Pipe

20210103 The exposition pipe %$%. is useful for commands that do not take a dataset as their argument but instead operates on vectors (such as columns from the dataset). An exposition pipe evaluates the following function within the context of the dataset passed to it, so that the variables of the dataset become available without the need to quote them. In our example we determine the correntlation between two columns, using stats::cor():

ds %>%
  filter(rainfall==0) %>%
  na.omit() %$%
  cor(min_temp, max_temp)

## [1] 0.7560283

Without an exposition pipe we might otherwise use base::with():

ds %>%
  filter(rainfall==0) %>%
  na.omit() %>%
  with(cor(min_temp, max_temp))

## [1] 0.7560283

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