Fix C/C++ problems causing R CMD CHECK errors.
melt.data.frame() throws when encountering objects of type POSIXlt,
and requests a conversion to the (much saner) POSIXct type.
melt.data.frame() now properly sets the OBJECT bit on value variable
generated if attributes are copied (for example, when multiple POSIXct
columns are concatenated to generate the value variable) (#50)
melt.data.frame() can melt data.frames containing list elements as id
columns. (#49)
melt.data.frame() no longer errors when measure.vars is NULL or empty.
(#46)
dcast() and acast() gain a useful error message if you use value_var
intead of value.var (#16), and if value.var doesn't exist (#9). They
also work better with . in specifications like . ~ . or
x + y ~ .
melt.array() creates factor variables with levels in the same order
as the original rownames (#19)
melt.data.frame() gains an internal Rcpp / C++ implementation, and
is now many orders of magnitudes faster. It also preserves identical
attributes for measure variables, and now throws a warning if they are
dropped. (Thanks to Kevin Ushey)
melt.data.frame() gains a factorsAsStrings argument that controls whether
factors are converted to character when melted as measure variables. This
is TRUE by default for backward compatibility.
melt.array() gains a as.is argument which can be used to prevent
dimnames being converted with type.convert()
recast() now returns a data frame instead of a list (#45).
Fix incompatibility with plyr 1.8
Fix evaluation bug revealed by knitr. (Fixes #18)
Fixed a bug in melt where it didn't automatically get variable names
when used with tables. (Thanks to Winston Chang)
Fixed bug in melt where factors were converted to integers, instead of to characters
When the measured variable is a factor, dcast now converts it to a
character rather than throwing an error. acast still returns a factor
matrix. (Thanks to Brian Diggs.)
acast is now much faster, due to fixing a very slow way of naming the
output. (Thanks to José Bartolomei Díaz for the bug report)
value_var argument to acast and dcast renamed to value.var to be
consistent with other argument names
Order NA factor levels before (all) when creating margins
Corrected reshape citation.
melt.data.frame no longer turns characters into factors
All melt methods gain a na.rm and value.name arguments - these
previously were only possessed by melt.data.frame (Fixes #5)