[R] return value of {....}

[akshay kulkarni]

dear Bert,
                   Thanks a lot...

Thanking you,
Yours sincerely,
AKSHAY M KULKARNI
________________________________
From: Bert Gunter <bgunter.4567 using gmail.com>
Sent: Monday, January 9, 2023 9:59 PM
To: akshay kulkarni <akshay_e4 using hotmail.com>
Cc: R help Mailing list <r-help using r-project.org>
Subject: Re: [R] return value of {....}

Unless you do something special within a function, only the value(s) returned are available to the caller. That is the essence of functional-type programming languages.

You need to read up on (function) environments in R . You can search on this. ?function and its links also contain useful information, but it may too terse to be explicable to you. There are of course many available references on the internet.

I believe your mental model for how R works is flawed, and you have some homework to do to correct it. I may be wrong, naturally, but you can judge by looking at some tutorials.

-- Bert

On Mon, Jan 9, 2023 at 6:47 AM akshay kulkarni <akshay_e4 using hotmail.com<mailto:akshay_e4 using hotmail.com>> wrote:
Dear members,
                             I have the following code:

> TB <- {x <- 3;y <- 5}
> TB
[1] 5

It is consistent with the documentation: For {, the result of the last expression evaluated. This has the visibility of the last evaluation.

But both x AND y are created, but the "return value" is y. How can this be advantageous for solving practical problems? Specifically, consider the following code:

F <- function(X) {  expr; expr2; { expr5; expr7}; expr8;expr10}

Both expr5 and expr7 are created, and are accessible by the code outside of the nested braces right? But the "return value" of the nested braces is expr7. So doesn't this mean that only expr7 should be accessible? Please help me entangle this (of course the return value of F is expr10, and all the other objects created by the preceding expressions are deleted. But expr5 is not, after the control passes outside of the nested braces!)

Thanking you,
Yours sincerely,
AKSHAY M KULKARNI

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