R help - Feb 2017 - How to use apply() to fill matrix by rows or columns?

Dear R,

I wanted to simulate a 5 by 3 matrix which fills up by either rows or
columns?

I started with the following filling the matrix by rows,

dat <- matrix(NA, nrow=5, ncol = 3)

for(i in 1:5){

    dat[i, ] <- rnorm(3)

}

But, R is known for no loop drama. Any suggestions?

Thanks!

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What is wrong with

dat <- matrix(rnorm(15), nrow=5, ncol = 3)

?

And what is this "no loop drama" you refer to? I use loops frequently
to loop around large memory gobbling chunks of code.

-- 
Sent from my phone. Please excuse my brevity.

On February 24, 2017 5:02:46 PM PST, C W <tmrsg11 at gmail.com>
wrote:
>Dear R,
>
>I wanted to simulate a 5 by 3 matrix which fills up by either rows or
>columns?
>
>I started with the following filling the matrix by rows,
>
>dat <- matrix(NA, nrow=5, ncol = 3)
>
>for(i in 1:5){
>
>    dat[i, ] <- rnorm(3)
>
>}
>
>But, R is known for no loop drama. Any suggestions?
>
>Thanks!
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

In theory, I am generating from group 5 groups of random numbers, each
group has 3 samples.

Isn't apply() the replacement of loops?

On Fri, Feb 24, 2017 at 8:23 PM, Jeff Newmiller <jdnewmil at
dcn.davis.ca.us>
wrote:
> What is wrong with
>
> dat <- matrix(rnorm(15), nrow=5, ncol = 3)
>
> ?
>
> And what is this "no loop drama" you refer to? I use loops
frequently to
> loop around large memory gobbling chunks of code.
>
> --
> Sent from my phone. Please excuse my brevity.
>
> On February 24, 2017 5:02:46 PM PST, C W <tmrsg11 at gmail.com>
wrote:
> >Dear R,
> >
> >I wanted to simulate a 5 by 3 matrix which fills up by either rows or
> >columns?
> >
> >I started with the following filling the matrix by rows,
> >
> >dat <- matrix(NA, nrow=5, ncol = 3)
> >
> >for(i in 1:5){
> >
> >    dat[i, ] <- rnorm(3)
> >
> >}
> >
> >But, R is known for no loop drama. Any suggestions?
> >
> >Thanks!
> >
> >       [[alternative HTML version deleted]]
> >
> >______________________________________________
> >R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >https://stat.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide
> >http://www.R-project.org/posting-guide.html
> >and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]