withVisible {base} R Documentation
Return both a Value and its Visibility
Description
This function evaluates an expression, returning it in a two element list containing its value and a flag showing whether it would automatically print.
Usage
withVisible(x)
Arguments
x
an expression to be evaluated.
Details
The argument, not an expression object, rather
an (unevaluated function) call , is evaluated in the
caller's context.
This is a primitive function.
Value
value
The value of x after evaluation.
visible
logical; whether the value would auto-print.
See Also
invisible , eval ;
withAutoprint() calls source() which
itself uses withVisible() in order to correctly
“auto print”.
Examples
x <- 1
withVisible(x <- 1) # *$visible is FALSE
x
withVisible(x) # *$visible is TRUE
# Wrap the call in evalq() for special handling
df <- data.frame(a = 1:5, b = 1:5)
evalq(withVisible(a + b), envir = df)
[Package base version 4.4.1 Index]