On Apr 26, 2012, at 3:40 PM, michaelyb wrote:
David -
My question to you may sound (actually, it really is) silly, but
please do
take your time to answer it.
What is the difference between:
fac<-function(x){a<-1
for (i in 1:x){
a<-a*i
}a}
and
David -
My question to you may sound (actually, it really is) silly, but please do
take your time to answer it.
What is the difference between:
fac<-function(x){a<-1
for (i in 1:x){
a<-a*i
}a}
and:
fac<-function(x){a<-1
for
Hello,
>
> gives you 120, but you cannot access it after the end of execution.
>
Because you're just printing the final value of 'a', not returning it.
fac <- function(x){
a <- 1
for(i in 1:x) a <- a*i
a
}
The return value must be the last instruction in a function.
The
the solution is to write functions that return the data you want changed, and
let the caller of the function decide where to put the answer. If you want to
return multiple "answers", collect them in a vector or list and return that.
---
In R, the preferred method is to assign the result to a new object:
fac <- function(x) {
a<-1
for(i in 1:x){
a<-a*i
print(a)
}
a # need to explicitly state what the function should return
}
myresult <- fac(5)
myresult
Sarah
On Thu, Apr 26, 2012 at 2:16 PM, michaelyb wrote:
>
On Apr 26, 2012, at 2:16 PM, michaelyb wrote:
Ista,
Since you seem to know your stuff very well, how would you get 120
out of a
function that gives you the factorial of 5, without using
factorial(5)?
Meanwhile, look at this example instead:
fac<-function(x){a<-1
for(i in
Simply return it like a function is supposed to:
fac <- function(x, loud = TRUE){
a <- 1
for(i in seq_len(x)) { # seq_len is faster and more robust
a <- a * i
if(loud) print(a)
}
return(a)
}
fac3 <- fac(3)
print(fac3) # As desired
Michael
On Thu, Apr 26, 2012 at
Ista,
Since you seem to know your stuff very well, how would you get 120 out of a
function that gives you the factorial of 5, without using factorial(5)?
> Meanwhile, look at this example instead:
> fac<-function(x){a<-1
> for(i in 1:x){
> a<-a*i
>
On Thu, Apr 26, 2012 at 1:32 PM, michaelyb wrote:
> Any solution for that type of problem?
Solution for what type of problem?
> I did read the ?"<<-", and seems very similar to the "assign" function, if I
> am not mistaken
Bottom line: don't use <<- until you know what you are doing. By the
Yes, don't do it.
I know this can seem appealing if you're coming from another language,
but playing fast and loose with globals, non-local effects, and
superassignment is almost-never a good idea.
Michael
On Thu, Apr 26, 2012 at 1:32 PM, michaelyb wrote:
> Any solution for that type of problem
Any solution for that type of problem?
I did read the ?"<<-", and seems very similar to the "assign" function, if I
am not mistaken
--
View this message in context:
http://r.789695.n4.nabble.com/Using-FUNCTION-to-create-usable-objects-tp4588681p4590445.html
Sent from the R help mailing list a
@r-project.org] On
> Behalf
> Of Ista Zahn
> Sent: Thursday, April 26, 2012 6:44 AM
> To: michaelyb
> Cc: r-help@r-project.org
> Subject: Re: [R] understanding the FUNCTION function
>
> On Thu, Apr 26, 2012 at 8:56 AM, michaelyb wrote:
> > Peter, your solution is actua
On Thu, Apr 26, 2012 at 8:56 AM, michaelyb wrote:
> Peter, your solution is actually very interesting. I have never seen or heard
> of before. I will look into it.
>
> Meanwhile, look at this example instead:
> fac<-function(x){a<-1
> for(i in 1:x){
> a<-a*i
>
Peter, your solution is actually very interesting. I have never seen or heard
of before. I will look into it.
Meanwhile, look at this example instead:
fac<-function(x){a<-1
for(i in 1:x){
a<-a*i
print(a)}}
The result is :
> fac(5)
[1] 1
[1] 2
[1]
I suspect you are trying to find
your way into Circle 6 of 'The R
Inferno' but haven't yet got in.
http://www.burns-stat.com/pages/Tutor/R_inferno.pdf
Pat
On 26/04/2012 03:06, michaelyb wrote:
Hello,
I am trying to understand why the FUNCTION used in several codes, won't
create the object af
In addition: the object MyNumberIs *is* created, but inside the
environment "attached" to the function as you evaluate it. And this
environment is gone when the function is done. (there is more to it, but
this is basically how it works). This is what Michael refers to in his
answer.
So, when
Functions are not subroutines; that is, the effects (including assignments) are
not global.
You need something like
F <- function(x) x
A <- F(3)
But that seems unnecessary...
A <- 3
Michael
On Apr 25, 2012, at 10:06 PM, michaelyb wrote:
> Hello,
>
> I am trying to understand why the FUNC
Hello,
I am trying to understand why the FUNCTION used in several codes, won't
create the object after it finishes running the code.
For instance, look at the following:
Number<- function(x) {MyNumberIs<-x}
When I run
Number(5)
Everything goes well, except that if I try to call the object MyNu
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