R help - Aug 2004 - displaying computation outputs inside "for" loops

Dear R-users,

I am puzzled by for loops and am kind of ashamed to ask because it is so
simple. There must be something I am missing in the way they are executed.

Basically, I would like to iterate a given number of time and generate a
bunch of stats (that's what loops are designed for, right?). Before doing
this I simply want to test simple procedure and see if they work (ie got the
syntax right - my main problem as I am new to R - and produce expected
results).

Even for something as basic as
for (i in 1:3) {i}

I get no screen output. Shouldn't R systematically display i for every loop
just like I am requesting with invoking "i"? When checking at the end
of the
looping, i is indeed assigned to 5 but I cannot get intermediate values.

Further testing shows that i takes all the values in
turn.
> for (i in 1:3) {str(i)}
 int 1
 int 2
 int 3

but summary(i) doesn't display anything. Isn't there something weird
with
this? Am I expecting something wrong and for loops just don't work that way,
unless using str() command? I tried print() and other descriptive commands
but to no avail.

A quick explanation would be grately appreciated

Thomas
***
Le contenu de cet e-mail et de ses pi??ces jointes est destin...{{dropped}}

Hi Thomas,

is this what you would like to get,

for(i in 1:3){
  x <- rnorm(5)
  cat("the values of `x' are:", format(x), "\n")
  cat("computation", i, "finished\n\n")
}

for(i in 1:3) print(i)


I hope this helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Doctoral Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Dewez Thomas" <t.dewez at brgm.fr>
To: "'R mailing list'" <r-help at stat.math.ethz.ch>
Sent: Monday, August 09, 2004 11:15 AM
Subject: [R] displaying computation outputs inside "for" loops

> Dear R-users,
>
> I am puzzled by for loops and am kind of ashamed to ask because it
is so
> simple. There must be something I am missing in the way they are
executed.
>
> Basically, I would like to iterate a given number of time and
generate a
> bunch of stats (that's what loops are designed for, right?). Before
doing
> this I simply want to test simple procedure and see if they work (ie
got the
> syntax right - my main problem as I am new to R - and produce
expected
> results).
>
> Even for something as basic as
> for (i in 1:3) {i}
>
> I get no screen output. Shouldn't R systematically display i for
every loop
> just like I am requesting with invoking "i"? When checking at the
end of the
> looping, i is indeed assigned to 5 but I cannot get intermediate
values.
>
> Further testing shows that i takes all the values in turn.
> > for (i in 1:3) {str(i)}
>  int 1
>  int 2
>  int 3
>
> but summary(i) doesn't display anything. Isn't there something
weird
with
> this? Am I expecting something wrong and for loops just don't work
that way,
> unless using str() command? I tried print() and other descriptive
commands
> but to no avail.
>
> A quick explanation would be grately appreciated
>
> Thomas
> ***
> Le contenu de cet e-mail et de ses pi??ces jointes est
destin...{{dropped}}
>
> ______________________________________________
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> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

On Mon, 9 Aug 2004, Dewez Thomas wrote:
> Dear R-users,
>
> I am puzzled by for loops and am kind of ashamed to ask because it is so
> simple. There must be something I am missing in the way they are executed.
>
If you want an explanation, rather than just a way to get printing, look
at FAQ 7.18.

	-thomas