May I ask how to initialize a list? usually I will use " result=list(0) " to do this. is this right? [[alternative HTML version deleted]]
On Mon, Jun 21, 2010 at 4:18 PM, song song <rprojecthelp at gmail.com> wrote:> May I ask how to initialize a list? > > usually I will use " result=list(0) " ?to do this. is this right?It works, but it is cleaner to use results=list() The difference is that list(0) will have one component that contains the number zero, whereas list() will simply initialize an empty list (no components). Peter
On Jun 21, 2010, at 7:18 PM, song song wrote:> May I ask how to initialize a list? > > usually I will use " result=list(0) " to do this. is this right?There is now something in that list, namely an element whose value is zero. If you append to it with the c() function, the 0 will still be there. > result=list(0) > result=c(result, 5) > result [[1]] [1] 0 [[2]] [1] 5 What's wrong with result=list() result=c(result, 5) > result [[1]] [1] 5 David Winsemius, MD West Hartford, CT
Use
result <- vector("list", n)
to make a list of length n, all of whose
components are NULL.
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org] On Behalf Of Peter Langfelder
> Sent: Monday, June 21, 2010 4:23 PM
> To: song song
> Cc: r-help at r-project.org
> Subject: Re: [R] how to initial a list to store data result?
>
> On Mon, Jun 21, 2010 at 4:18 PM, song song
> <rprojecthelp at gmail.com> wrote:
> > May I ask how to initialize a list?
> >
> > usually I will use " result=list(0) " ?to do this. is this
right?
>
> It works, but it is cleaner to use
>
> results=list()
>
> The difference is that list(0) will have one component that contains
> the number zero, whereas list() will simply initialize an empty list
> (no components).
>
> Peter
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
Bill.Venables at csiro.au
2010-Jun-22 00:22 UTC
[R] how to initial a list to store data result?
The usual method is either
lis <- vector("list")
or, nearly equivalently,
lis <- list()
If you know in advance how many components the list will have, there can be a
slight advantage in using
lis25 <- vector("list", 25)
if e.g. you know the list will be of length 25.
Bill Venables.
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of song song
Sent: Tuesday, 22 June 2010 9:18 AM
To: r-help at r-project.org
Subject: [R] how to initial a list to store data result?
May I ask how to initialize a list?
usually I will use " result=list(0) " to do this. is this right?
[[alternative HTML version deleted]]
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.