Another option is
Filter(function(x) x[1] == 1, foo)
Best,
luke
On Sat, 12 Jul 2014, ce wrote:
Thanks Jeff et. all,
This is exactly what I needed.
-----Original Message-----
From: "Jeff Newmiller" [jdnew...@dcn.davis.ca.us]
Date: 07/12/2014 10:38 AM
To: "Uwe Ligges" <lig...@statistik.tu-dortmund.de>, "ce" <zadi...@excite.com>,
r-help@r-project.org
Subject: Re: [R] lapply returns NULL ?
I think that removing them is something the OP doesn't understand how to do.
The lapply function ALWAYS produces an output element for every input element.
If this is not what you want then you need to choose a looping structure that
is not so tightly linked to the input, such as a for loop (untested):
result <- list()
for (nm in names(foo)) {
if ( 1 == foo[[nm]][1] ) {
result[[ nm ]] <- foo[[ nm ]]
}
}
result
or use vector indexing (lists are a special kind of vector) with the loop
result:
foo[ sapply(foo,function(v){1==v[1]}) ]
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On July 12, 2014 6:37:44 AM PDT, Uwe Ligges <lig...@statistik.tu-dortmund.de>
wrote:
On 12.07.2014 15:25, ce wrote:
Dear all,
I have a list of arrays :
foo<-list(A = c(1,3), B =c(1, 2), C = c(3, 1))
foo
$A
[1] 1 3
$B
[1] 1 2
$C
[1] 3 1
if( foo$C[1] == 1 ) foo$C[1]
lapply(foo, function(x) if(x[1] == 1 ) x )
$A
[1] 1 3
$B
[1] 1 2
$C
NULL
I don't want to list $C NULL in the output. How I can do that ?
Either use your own print function or, if you do not want NULL elements
in the object, remove them.
Best,
Uwe Ligges
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______________________________________________
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and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
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and provide commented, minimal, self-contained, reproducible code.
--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
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______________________________________________
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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.
