Tyler Rinker Tyler Rinker - 2 months ago 15
R Question

Stop lapply from printing to console

When I use

lapply
and print to the console it prints unwanted
[[i]]NULL
though I want the intended message to print to the console. I've tried
suppressWarnings
and
suppressMessages
but these do not remove the unwanted offender. I searched
lapply
and don't see an argument to silence it. This is more aesthetic as it doesn't interfere with the function. I'm not opposed to allternative printing to the console so long as the user can turn it off if they wish.

Here's an example function, the output and what I'd like to get:

Sample function:

FUN <- function(x) {
FUN2 <- function(z) message(z)
lapply(1:3, function(i) FUN2(paste(x, i)))
}

FUN("hello")


Output:

hello 1
hello 2
hello 3
[[1]]
NULL

[[2]]
NULL

[[3]]
NULL


Desired Output:

hello 1
hello 2
hello 3

Answer

Use invisible, eg:

invisible(FUN("hello"))
hello 1
hello 2
hello 3

You can wrap it around the lapply call in the function too to make it tidier.

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