Dear friends,
How do I stop partial matching of list names?
e.g.,
x <- list(AAAA="aaaaa", BBBBB="bbbbb")
is.null(x$A) #returns FALSE even though there is no element A.
if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A}
result #is aaaa even though there is no x$A element
x <- list(CCCC="aaaaa", BBBBB="bbbbb")
if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A}
result #this is great
x <- list(ABC="aaaaa", BBBBB="bbbbb")
if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A}
result #partial matches and returns aaaa
x <- list(ABC="abc", BBBBB="bbbbb",AA="aaaa")
if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A}
result #can not partial match, and thus returns bbbb
x <- list(AAB="aab", BBBBB="bbbbb",AA="aaaa")
if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A}
result #also can not partial match
My need for this is that I have several functions that return lists
and I am trying to extract AAAA if it exists, but something else if
it does not.
Thanks.
Bill
--
William Revelle http://personality-project.org/revelle.html
Professor http://personality-project.org
Department of Psychology http://www.wcas.northwestern.edu/psych/
Northwestern University http://www.northwestern.edu/
Use R for psychology http://personality-project.org/r
It is 6 minutes to midnight http://www.thebulletin.org
On Sun, May 8, 2011 at 11:09 AM, William Revelle <lists at revelle.net> wrote:> Dear friends, > > How do I stop partial matching of list names? > > e.g., > > x <- list(AAAA="aaaaa", BBBBB="bbbbb") > is.null(x$A) ? #returns FALSE ?even though there is no element A. > > if(is.null(x$A)) ?{result <- ?x$BBBB} else {result <- x$A} > result ? #is aaaa even though there is no x$A element >x[["A"]] -thomas -- Thomas Lumley Professor of Biostatistics University of Auckland
On 07/05/2011 7:09 PM, William Revelle wrote:> Dear friends, > > How do I stop partial matching of list names? > > e.g., > > x<- list(AAAA="aaaaa", BBBBB="bbbbb") > is.null(x$A) #returns FALSE even though there is no element A. > > if(is.null(x$A)) {result<- x$BBBB} else {result<- x$A} > result #is aaaa even though there is no x$A element > > x<- list(CCCC="aaaaa", BBBBB="bbbbb") > if(is.null(x$A)) {result<- x$BBBB} else {result<- x$A} > result #this is great > > x<- list(ABC="aaaaa", BBBBB="bbbbb") > if(is.null(x$A)) {result<- x$BBBB} else {result<- x$A} > result #partial matches and returns aaaa > > x<- list(ABC="abc", BBBBB="bbbbb",AA="aaaa") > if(is.null(x$A)) {result<- x$BBBB} else {result<- x$A} > result #can not partial match, and thus returns bbbb > > x<- list(AAB="aab", BBBBB="bbbbb",AA="aaaa") > if(is.null(x$A)) {result<- x$BBBB} else {result<- x$A} > result #also can not partial match > > My need for this is that I have several functions that return lists > and I am trying to extract AAAA if it exists, but something else if > it does not.Both "A" %in% names(x) will return false, and is.null(x[["A"]]) will return TRUE. Duncan Murdoch
> Dear friends, > > How do I stop partial matching of list names? > > e.g., > > x <- list(AAAA="aaaaa", BBBBB="bbbbb") > is.null(x$A) #returns FALSE even though there is no element A. > > if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A} > result #is aaaa even though there is no x$A element > > x <- list(CCCC="aaaaa", BBBBB="bbbbb") > if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A} > result #this is great > > x <- list(ABC="aaaaa", BBBBB="bbbbb") > if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A} > result #partial matches and returns aaaa > > x <- list(ABC="abc", BBBBB="bbbbb",AA="aaaa") > if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A} > result #can not partial match, and thus returns bbbb > > x <- list(AAB="aab", BBBBB="bbbbb",AA="aaaa") > if(is.null(x$A)) {result <- x$BBBB} else {result <- x$A} > result #also can not partial match > > My need for this is that I have several functions that return lists > and I am trying to extract AAAA if it exists, but something else if > it does not.ifelse("AAAA" %in% names(x),x[["AAAA"]],x[["BBBB"]]) HTH, Denes> > Thanks. > > Bill > > -- > William Revelle http://personality-project.org/revelle.html > Professor http://personality-project.org > Department of Psychology > http://www.wcas.northwestern.edu/psych/ > Northwestern University http://www.northwestern.edu/ > Use R for psychology > http://personality-project.org/r > It is 6 minutes to midnight http://www.thebulletin.org > > ______________________________________________ > 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. >