mutate() adds new variables; transmute() keeps the newly created variables
along with index and keys;
# S3 method for tbl_ts
mutate(.data, ..., .drop = FALSE)# S3 method for tbl_ts
transmute(.data, ..., .drop = FALSE)
A tsibble.
Name-value pairs of expressions.
FALSE returns a tsibble object as the input. TRUE drops a
tsibble and returns a tibble.
These column-wise verbs from dplyr have an additional argument of .drop = FALSE
for tsibble. The index variable cannot be dropped for a tsibble. If any key
variable is changed, it will validate whether it's a tsibble internally.
Turning .drop = TRUE converts to a tibble first and then do the operations.
summarise() will not collapse on the index variable.