The function captures both output and expected messages from an R expression. If the expression results in an unexpected message, an error is issued.
Usage
capture_output(expr, srcref = NULL, expected_cnds = NULL, env = caller_env())Arguments
- expr
An R expression to evaluate
- Permitted values
An unquoted R expression
- Default value
none
- srcref
The source reference of the expression
- Default value
NULL
- expected_cnds
A character vector of expected conditions
If the expression issues a condition of a class that is in this vector, the condition is ignored but added to the return value.
Otherwise, an error is issued.
- Default value
NULL
- env
The environment in which to evaluate the expression
- Default value
Examples
Capture Output and Messages
capture_output(1 + 1)
#> [1] "[1] 2"
capture_output(log(-1))
#> Error in capture_output(log(-1)) : The expression
#> > log(-1)
#> issued an unexpected condition:
#> NaNs produced
#> If this is expected, add any of the classes "simpleWarning", "warning", and
#> "condition" to the argument `expected_cnds`.
capture_output(log(-1), expected_cnds = "warning")
#> [1] "[1] NaN" "Warning in log(-1) : NaNs produced"