R help - Jan 2013 - Merging list of dataframes with reshape merge_all

Hi,

I'd like to merge mutliple dataframes from a list of dataframes by some
common
columns. The approach for simply merging 2 dataframes is working with:

merge(df1,df2,by=c("col1","col2","col3"),all=TRUE)

For mutliple dataframes in a list I try to use the merge_all command
from the package reshape.
The documentation states that the command takes a list of dataframes
and other additional
argument which are passed on to merge. So I tried (just for the case
of two dataframes):

merge_all(list(df1,df2),by=c("col1","col2","col3"),all=TRUE)

but I get following error:
Error in merge.data.frame(dfs[[1]], dfs[[2]], all = TRUE, sort = FALSE,  :
  formal argument "all" matched by multiple actual arguments

What do I need to do to solve that problem?

PS: Just a related side-question: Why is merge_all not included in the
"newer" package reshape2 as this is considered to be a reboot of the
reshape package?

/johannes

Hello,

To "solve" the problem you can use all.x and all.y but I think there
are
other problems with merge_all, in the example below it doesn't include 
df2$Y in the result df.


df1 <- data.frame(col1=1:10, col2=11:20, col3=21:30, X = rnorm(10))
df2 <- data.frame(col1=1:10, col2=11:20, col3=21:30, Y = rnorm(10))

merge_all(list(df1, df2),
by=c("col1","col2","col3"), all.x=TRUE,
all.y=TRUE)  # No Y column
merge(df1, df2, by=c("col1","col2","col3"),
all.x=TRUE, all.y=TRUE)


Contact the package maintainer for more info.

maintainer('reshape')
[1] "Hadley Wickham <h.wickham at gmail.com>"


Hope this helps,

Rui Barradas

Em 11-01-2013 10:08, Johannes Radinger escreveu:
> Hi,
>
> I'd like to merge mutliple dataframes from a list of dataframes by some
common
> columns. The approach for simply merging 2 dataframes is working with:
>
>
merge(df1,df2,by=c("col1","col2","col3"),all=TRUE)
>
> For mutliple dataframes in a list I try to use the merge_all command
> from the package reshape.
> The documentation states that the command takes a list of dataframes
> and other additional
> argument which are passed on to merge. So I tried (just for the case
> of two dataframes):
>
>
merge_all(list(df1,df2),by=c("col1","col2","col3"),all=TRUE)
>
> but I get following error:
> Error in merge.data.frame(dfs[[1]], dfs[[2]], all = TRUE, sort = FALSE,  :
>    formal argument "all" matched by multiple actual arguments
>
> What do I need to do to solve that problem?
>
> PS: Just a related side-question: Why is merge_all not included in the
> "newer" package reshape2 as this is considered to be a reboot of
the
> reshape package?
>
> /johannes
>
> ______________________________________________
> R-help at 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.

> PS: Just a related side-question: Why is merge_all not included in the
> "newer" package reshape2 as this is considered to be a reboot of
the
> reshape package?
Because it doesn't work very well, as you've discovered.

There's an equivalent join_all in plyr.

Hadley

-- 
Chief Scientist, RStudio
http://had.co.nz/