[R] Using apply function to merge list of data frames

[S Ellison]

Short answer: do.call()

do.call("rbind", df.list)
will rbind all of the data frames in df.list.

You may have to tidy up row names afterwards, and you will need to make sure that the data frames all have the same column names and each column has the same class, or you'll get unexpected results.

S Ellison

> -----Original Message-----
> From: R-help [mailto:r-help-bounces using r-project.org] On Behalf Of Naresh
> Gurbuxani
> Sent: 25 July 2018 07:17
> To: R-help using r-project.org
> Subject: [R] Using apply function to merge list of data frames
> 
> I have a list whose components are data frames.  My goal is to construct a
> data frame by merging all the list components.  Is it possible to achieve this
> using apply and without a for loop, as used below?
> 
> Thanks,
> Naresh
> 
> mylist <- list(A = data.frame(date = seq.Date(as.Date('2018-01-01'), by =
> 'week',
>                                   length.out = 5), ret = rnorm(5)),
>                B = data.frame(date = seq.Date(as.Date('2018-01-01'), by = 'week',
>                                   length.out = 5), ret = rnorm(5)))
> 
> mydf <- data.frame(date = seq.Date(as.Date('2018-01-01'), by = 'week',
> length.out = 5))
> 
> for(ch in names(mylist)){
>     tempdf <- mylist[[ch]]
>     names(tempdf)[2] <- paste(names(tempdf)[2], ch, sep = '.')
>     mydf <- merge(mydf, tempdf, by = c('date'))}
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