Documentation about melt.data.table in data.table

Question

I want to read more details about the new function in data.table v 1.8.11, after reading the link

I tried ?melt.data.table as pointed in the above link. But there's no documents..

No documentation for melt.data.table?in specified packages and libraries: you could try ??melt.data.table?

Here's my sessionInfo()

R version 3.0.2 (2013-09-25)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252 LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] data.table_1.8.11

Did I miss something?

EDIT On Jan20 2014

** Problems Still Not Solved**

I tried unistalled the data.table and deleted the library directory.

And then installed using the precompiled for windows in this link

> install.packages("~/Downloads/data.table_1.8.11.zip", repos = NULL)
Warning in install.packages :
  package 憕/Downloads/data.table_1.8.11.zip?is not available (for R version 3.0.2)
Installing package into 慍:/Users/James/R/win-library/3.0?(as 憀ib?is unspecified)
package 慸ata.table?successfully unpacked and MD5 sums checked

The sessionInfo() is the same after reinstalling, and I put all the information here. Still the ?melt.data.table not working.

Strange, seems to work just fine for me. Both `?melt` and `?melt.data.table` work... — Arun, Jan 19 '14 at 16:20
Hey, Arun, I didn't get any error when loading data.table. It's weird. — Bigchao, Jan 19 '14 at 17:46
I think you've to install `reshape2` package. Not sure how you got `data.table` installed without warning/error... — Arun, Jan 19 '14 at 20:22
@Arun I updated the problem. I got a warning when installing. and it still doesn't work. Also, I installed reshape2, is there a conflict? — Bigchao, Jan 20 '14 at 05:01
Try installing from [here](http://datatable.r-forge.r-project.org/data.table_1.8.11.zip). That's the latest pre-compiled link for Windows. — Arun, Jan 20 '14 at 12:57
@Arun Thanks for your attetion. I installed again, but still not working. Sigh... — Bigchao, Jan 21 '14 at 04:14

score 3 · Accepted Answer · edited Feb 04 '14 at 12:34

3

[Edit by Matt] In turns out the data.table homepage was misleading (now fixed) and the Windows .zip on that page was 5 months old.

The correct way to install from R-Forge is

install.packages("data.table", repos="http://R-Forge.R-project.org").

Then the problem is solved and the documentation for ?melt.data.table is available.

edited Feb 04 '14 at 12:34

Matt Dowle

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answered Feb 04 '14 at 12:14

Bigchao

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score 0 · Answer 2 · answered Jan 19 '14 at 19:51

Sorry this belongs in a comment but it's too long...

You might want to try re-installing data.table 1.8.11 (I found it here). When I do that, then start a new R session and:

library(data.table)
# data.table 1.8.11  For help type: help("data.table")

sessionInfo()
# R version 3.0.2 (2013-09-25)
# Platform: x86_64-w64-mingw32/x64 (64-bit)
#
# locale:
# [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252    LC_MONETARY=English_United States.1252
# [4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    
#
# attached base packages:
# [1] stats     graphics  grDevices utils     datasets  methods   base     
#
# other attached packages:
# [1] data.table_1.8.11
#
# loaded via a namespace (and not attached):
# [1] plyr_1.8       reshape2_1.2.2 stringr_0.6.2  tools_3.0.2

Note the bit at the end. It looks like data.table 1.8.11 loads reshape2, which probably contains melt.data.table(...). Did you truncate your sessionInfo, or were they not loaded?

`reshape2` does not contain any `data.table` methods. `data.table` just builds on the S3 generic (for `reshape2:::melt` atm) from it. — Arun, Jan 19 '14 at 20:22
@jlhoward, I put all the information here, it seems that they were not loaded. — Bigchao, Jan 20 '14 at 04:55

Documentation about melt.data.table in data.table

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