Adverbs take a function and return a modified function.
silently()
silently()
transforms a function so that when you call
this new function, it returns nothing unless there is an error or a
warning (contrary to attempt
that returns the result). In a
sense, the new function stay silent unless error or warning.
silent_log <- silently(log)
silent_log(1)
silent_log("a")
#> Error in .f(...) : non-numeric argument to mathematical function
# Error in .f(...) : non-numeric argument to mathematical function
With silently()
, the result is never returned.
silent_matrix <- silently(matrix)
silent_matrix(1:3, 2)
#> Warning in .f(...): data length [3] is not a sub-multiple or multiple of the
#> number of rows [2]
# Warning message:
# In .f(...) :
# data length [3] is not a sub-multiple or multiple of the number of rows [2]
surely()
surely()
transforms a function so that when you call
this new function, it calls attempt()
- i.e. in the code
below, calling sure_log(1)
is the same as calling
attempt(log(1))
. In a sense, you’re sure this new function
will always work.
sure_log <- surely(log)
sure_log(1)
#> [1] 0
# [1] 0
sure_log("a")
#> Error: non-numeric argument to mathematical function
# Error: non-numeric argument to mathematical function
with_message()
and with_warning()
These two functions take a function, and add a warning or a message
to it.
as_num_msg <- with_message(as.numeric, msg = "We're performing a numeric conversion")
as_num_warn <- with_warning(as.numeric, msg = "We're performing a numeric conversion")
as_num_msg("1")
#> We're performing a numeric conversion
#> [1] 1
as_num_warn("1")
#> Warning in as_num_warn("1"): We're performing a numeric conversion
#> [1] 1
without_message()
, without_warning()
, and
discretly()
These three functions do the opposite, as they remove warnings and
messages:
matrix(1:3, ncol = 2)
#> Warning in matrix(1:3, ncol = 2): data length [3] is not a sub-multiple or
#> multiple of the number of rows [2]
#> [,1] [,2]
#> [1,] 1 3
#> [2,] 2 1
no_warning_matrix <- without_warning(matrix)
no_warning_matrix(1:3, ncol = 2)
#> [,1] [,2]
#> [1,] 1 3
#> [2,] 2 1