On 2011-05-21 23:11, Jeroen Ooms wrote:
I need to convert a dataframe to a record-structure, to be able to encode it
later in JSON. Suppose this is the data:
mydata<- data.frame(foo=1:3, bar=c("M","M","F"));
I would like to convert this to a unnamed list (json array) of key-value
pairs. For example like this:
apply(data.frame(foo=1:3, bar=c("M","M","F")),1,as.list)
However, when I do this, all the numeric values are converted to strings. I
don't understand why this is, because when I try to convert one record
simulataniously, this does not happen:
But it does; see below;
as.list(mydata[1,]);
This avoids apply. Try:
apply(mydata[1,], 1, as.list)
and you'll get the conversion of numerics to strings. apply() operates
on arrays and a data frame will be coerced to a matrix (which requires
all elements to be of the same type). This is documented in ?apply.
I am not sure if this is indended behaviour or not, but is there an elegant
way to apply 'as.list' to all of the dataframe rows without coercing
everything to strings?
This may not be elegant, but why not just use a loop:
L <- vector("list", 3)
for( i in 1:3 ) L[[i]] <- as.list(mydata[i, ])
Peter Ehlers
--
View this message in context:
http://r.789695.n4.nabble.com/unwanted-coercion-using-apply-tp3541637p3541637.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.
______________________________________________
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.
