Dimension Mismatch using melt() in reshape2

[samzipper]

Modified from StackOverflow:
http://stackoverflow.com/questions/36461653/dimension-mismatch-using-melt-in-reshape2

I am trying to melt a data frame from 'wide' format to 'long' format in R, using the function 'melt' in the package 'reshape2'. However, I am encountering an issue with dimensions when trying to view the output data frame which I am having trouble deciphering. Here is an example:

# load reshape2 package
require(reshape2)

# sample data frame generated using dput
df <- structure(list(year = c(2001, 2002, 2003, 2004), 
                     aet = structure(c(493.1, 407.1, 476.7, 501.6), .Dim = 4L), 
                     drainage = structure(c(5.4, 5.4, 5.4, 5.4), .Dim = 4L), 
                     srunoff = structure(c(25.6, 24.3, 56.0, 50.3), .Dim = 4L)),
                .Names = c("year", "aet", "drainage", "srunoff"), row.names = c(NA, 4L), class = "data.frame")

# if i melt without specifying id.vars, it provides a warning but works works fine
df.melt <- melt(df)

# check output
head(df.melt)

# view output
View(df.melt)
# this works fine, and the data frame is visible in RStudio

# now, melt while supplying year as an id variable
df.melt.id <- melt(df, id.vars="year")

# check output
head(df.melt.id)
# the first 6 lines of output print to the console menu, as normal

# view output
View(df.melt.id)

However, when I try to view the df.melt.id data frame, I get the following error:

Error in FUN(X[[i]], ...) : 
  dims [product 4] do not match the length of object [12]

4 corresponds to the original length of the data frame, and 12 is how long it should be. If I check the dimensions using dim(df.melt.id), it returns the appropriate size: [1] 12 3

Using 'melt' from the original reshape package, everything works fine:

df.melt.id <- reshape::melt(df, id.vars="year")

[kevinushey]

The problem here is that the dimension attribute on the value variable is not getting dropped (updated?) post-melt.

[TPucke]

Still a problem in reshape2 installed today (v1.4.3). I worked around it by making the attribute NULL myself. Not the best. I can confirm that it works ok when the data.frame columns are assigned using as.vector conversion from array. The issue happens when the column as assigned a value of array type.

[DavidykZhao]

I encountered the same issue today. However, it worked when I used the original reshape package.