[R] merging several dataframes from a list

[Antje]

Gabor Grothendieck schrieb:
> What version of R are you using? 

"R version 2.8.1 (2008-12-22)" (running Windows)



I get this:
> 
>> do.call(cbind, mylist)
>   df1.pos df1.data df2.pos df2.data df3.pos df3.data
> 1       A        2       A        6       A        9
> 2       B        6       B        2       B        3
> 3       C        3       C        9       C        6
> 4       D        1       D        7       D        2
> 5       E        9       E        5       E        1
>> R.version.string
> [1] "R version 2.8.1 Patched (2008-12-26 r47350)"
> 
> In which case
> 
>> ALL <- do.call(cbind, mylist)
>> ALL <- ALL[regexpr("data", names(ALL)) > 0]
>> names(ALL) <- sub("[.].*", "", names(ALL))
>> ALL
>   df1 df2 df3
> 1   2   6   9
> 2   6   2   3
> 3   3   9   6
> 4   1   7   2
> 5   9   5   1
> 
> 
> On Wed, Jan 21, 2009 at 3:19 AM, Antje <niederlein-rstat at yahoo.de> wrote:
>> Hi there,
>>
>> I have a list of dataframes (generated by reading multiple files) and all
>> dataframes are comparable in dimension and column names. They also have a
>> common column, which, I'd like to use for merging. To give a simple example
>> of what I have:
>>
>> df1 <- data.frame(c(LETTERS[1:5]), c(2,6,3,1,9))
>> names(df1) <- c("pos", "data")
>> df3 <- df2 <- df1
>> df2$data <- c(6,2,9,7,5)
>> df3$data <- c(9,3,6,2,1)
>> mylist <- list(df1,df2,df3)
>> names(mylist) <- c("df1","df2","df3")
>>
>>> mylist
>> $df1
>>  pos data
>> 1   A    2
>> 2   B    6
>> 3   C    3
>> 4   D    1
>> 5   E    9
>>
>> $df2
>>  pos data
>> 1   A    6
>> 2   B    2
>> 3   C    9
>> 4   D    7
>> 5   E    5
>>
>> $df3
>>  pos data
>> 1   A    9
>> 2   B    3
>> 3   C    6
>> 4   D    2
>> 5   E    1
>>
>> If I use do.call("cbind"), I'll end up with something like this
>>
>>   pos data pos data pos data
>> 1   A    2   A    6   A    9
>> 2   B    6   B    2   B    3
>> 3   C    3   C    9   C    6
>> 4   D    1   D    7   D    2
>> 5   E    9   E    5   E    1
>>
>>
>> but now, I don't know anymore which data comes from which dataframe... and I
>> have the column "pos" multiple times...
>>
>> Instead I'd like to have it like this:
>>
>>   pos df1 df2 df3
>> 1   A    2   6   9
>> 2   B    6   2   3
>> 3   C    3   9   6
>> 4   D    1   7   2
>> 5   E    9   5   1
>>
>> How, can I realize it? (The list, I'm working with has not just 3 data
>> frames like given in my example, so I need to automize it)
>>
>>
>> Antje
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>