J. Mini questions

• How are apply family functions scoped?
• R's switch statement is not a special form, is it therefore slow?
• Can R Markdown be made to preview from anywhere other than the start of the document?
• How can I make R's output more verbose so as to reassure me that it hasn't broken yet?
• Does R have a way to say "do n times" without having to write a for loop with a redundant variable?
• Is Clojure less homoiconic than other lisps? [closed]
• How do you say `[` and `[[`?
• What can a data frame do that a tibble cannot?
• Where is the Purrr ~ operator documented?
• How can I avoid writing nested for loops for large data sets?

J. Mini answers