R help - Jun 2010 - Are any values in one list contained within a second list

Silly question, but, can I test to see if any value of list a is contained in
list b without doing a loop? A loop is easy enough, but wanted to see if
there was a cleaner way. By way of example:

List 1: a, b, c, d, e, f, g

List 2: z, y, x, w, v, u, b

Return true, since both lists contain b

List 1: a, b, c, d, e, f, g

List 2: z, y, x, w, v, u, t

Return false, since the lists have no mutual values



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Hi GL,

Tr this:

# example 1

list1 <- list(letters[1:7])

list1

list2 <-
list(c('z','y','x','w','v','u','b'))

list2

mapply(function(x, y) any(x %in% y), list1, list2)



 # example 2

list2 <-
list(c('z','y','x','w','v','u','t'))

list2

mapply(function(x, y) any(x %in% y), list1, list2)

HTH,
Jorge


On Sun, Jun 13, 2010 at 2:17 PM, GL <> wrote:
>
> Silly question, but, can I test to see if any value of list a is contained
> in
> list b without doing a loop? A loop is easy enough, but wanted to see if
> there was a cleaner way. By way of example:
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, b
>
> Return true, since both lists contain b
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, t
>
> Return false, since the lists have no mutual values
>
>
>
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/Are-any-values-in-one-list-contained-within-a-second-list-tp2253637p2253637.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
> 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]]

On Jun 13, 2010, at 2:17 PM, GL wrote:
>
> Silly question, but, can I test to see if any value of list a is  
> contained in
> list b without doing a loop? A loop is easy enough, but wanted to  
> see if
> there was a cleaner way. By way of example:
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, b
>
> Return true, since both lists contain b
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, t
>
> Return false, since the lists have no mutual values
length(intersect(List_1, List_2)) > 0
>

David Winsemius, MD
West Hartford, CT

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of GL
> Sent: Sunday, June 13, 2010 11:18 AM
> To: r-help at r-project.org
> Subject: [R] Are any values in one list contained within a second list
> 
> 
> Silly question, but, can I test to see if any value of list a 
> is contained in
> list b without doing a loop?
It is almost the same as your English description of the problem:
  any(a %in% b)
> A loop is easy enough, but 
> wanted to see if
> there was a cleaner way. By way of example:
> 
> List 1: a, b, c, d, e, f, g
> 
> List 2: z, y, x, w, v, u, b
It would be nicer if you used R syntax to create the
datasets in your example.  E.g., I'm guessing you mean
     a1 <-
c("a","b","c","d","e","f","g")
but since you didn't quote the strings and you called it
a "list" you could mean
     a2 <- as.list(expression(a, b, c, d, e, f, g))
or, equivalently,
     a3 <- list(quote(a), quote(b), quote(c), quote(d), quote(e),
quote(f), quote(g))

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com  
> 
> Return true, since both lists contain b
> 
> List 1: a, b, c, d, e, f, g
> 
> List 2: z, y, x, w, v, u, t
> 
> Return false, since the lists have no mutual values
> 
> 
> 
> -- 
> View this message in context: 
> http://r.789695.n4.nabble.com/Are-any-values-in-one-list-conta
ined-within-a-second-list-tp2253637p2253637.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>

I think the simplest way is to translate the English
directly :-)
> list1 =
c('a','b','c','d','e','f','g')
> list2 =
c('z','y','x','w','v','u','b')
> any(list2 %in% list1)
[1] TRUE
> list2 =
c('z','y','x','w','v','u','t')
> any(list2 %in% list1)
[1] FALSE

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Sun, 13 Jun 2010, GL wrote:
>
> Silly question, but, can I test to see if any value of list a is contained
in
> list b without doing a loop? A loop is easy enough, but wanted to see if
> there was a cleaner way. By way of example:
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, b
>
> Return true, since both lists contain b
>
> List 1: a, b, c, d, e, f, g
>
> List 2: z, y, x, w, v, u, t
>
> Return false, since the lists have no mutual values
>
>
>
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/Are-any-values-in-one-list-contained-within-a-second-list-tp2253637p2253637.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>