[R] Merging list of dataframes with reshape merge_all

[Johannes Radinger]

Hi Rui,

thank you so far for your answer...
...as i found these other problems also myself, I decided to go
for a looping apporach with the base merge command and always
add a new dataframe to the old one (growing dataframe).

/johannes

On Fri, Jan 11, 2013 at 1:26 PM, Rui Barradas <ruipbarradas at sapo.pt> wrote:
> 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
>>
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>
>