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)