Žroutík wrote:
Dear R-users,

in a minimal example exists() gives FALSE on an object which obviously does
exist. How can I check on that list object anyway else, please?

SmoothData <- list(exists=TRUE, span=0.001)
SmoothData
$exists
[1] TRUE

$span
[1] 0.001

exists("SmoothData")
TRUE
exists("SmoothData$span")
FALSE
This checks for existance of an object called "SmoothData$span", as in :

`SmoothData$span` <- 1:10
exists("SmoothData$span")

You can do:

is.list( SmoothData ) && !is.null(names(SmoothData)) && "span" %in% names(SmoothData)

exists("SmoothData[[2]]")
FALSE
Similarly:

`SmoothData[[2]]` <- 1
exists("SmoothData[[2]]")

You can do:

is.list( SmoothData ) && length(SmoothData) > 1

Thank you for any opinion regarding this topic.
Zroutik


--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr

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