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
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