[R] can this be simplified with purrr:map or mapply?

[Ulrik Stervbo]

If you want to use purrr, you could do

fil <- paste0("data",2004:2014,".txt")
map_df(fil, read.table, .id = "fil")

to get everything in one data frame (I assume all files have the same
structure)

HTH
Ulrik

On Wed, 18 Jan 2017 at 16:10 PIKAL Petr <petr.pikal at precheza.cz> wrote:

> Hi
>
> Let me make some assumptions. Your data are stored as *txt files somewhere.
>
> I would start with vector of file names
>
> fil<-paste0("data",2004:2014,".txt")
> > fil
>  [1] "data2004.txt" "data2005.txt" "data2006.txt" "data2007.txt"
> "data2008.txt"
>  [6] "data2009.txt" "data2010.txt" "data2011.txt" "data2012.txt"
> "data2013.txt"
> [11] "data2014.txt"
>
> than I would read my files into predefined list
>
> mylist<-vector(length=11, mode="list")
>
> You can add names to this list by
> names(mylist) <- fil
>
> Than simple cycle
>
> for (i in seq_along(fil)) {
>
> mylist[[i]] <- read.table(fil[i])
>
> ... you could also do some polishing of single files here
> }
>
> Now you have list of data frames and you can do many operations on this
> whole list instead on separate data frames.
>
> Further operations depend on structure of your data frames and your exact
> intention what do you want to do with them.
>
> I wonder why merge is appropriate if you have separate data for each year.
> Why not to use rbind followed by aggregate.
>
> But here I am fishing in really murky water.
>
> Cheers
> Petr
>
>
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Brandon
> > Payne
> > Sent: Wednesday, January 18, 2017 10:57 AM
> > To: r-help at r-project.org
> > Subject: [R] can this be simplified with purrr:map or mapply?
> >
> > I can't get my head around the *apply family of functions,
> > surely there's a better way than what I have.
> > I've tried using paste0 on the years, but then I have lists of strings,
> not
> > data frames.
> >
> > `realList<-paste0("exp",as.character(2004:2014),"s")`
> >
> > I can't seem to convert these lists of strings to references to data
> frames.
> >
> > years<-c(2004:2014)
> > framesEXP<-
> > list(exp2004s,exp2005s,exp2006s,exp2007s,exp2008s,exp2009s,exp2011s,ex
> > p2010s,exp2012s,exp2013s,exp2014s)
> >
> > framesFAM<-
> > list(fam2004s,fam2005s,fam2006s,fam2007s,fam2008s,fam2009s,fam2011s,fa
> > m2010s,fam2012s,fam2013s,fam2014s)
> >
> > data2004<<-merge(exp2004s,fam2004s, by="HHNUM")
> > data2005<<-merge(exp2005s,fam2005s, by="HHNUM")
> > data2006<<-merge(exp2006s,fam2006s, by="HHNUM")
> > data2007<<-merge(exp2007s,fam2007s, by="HHNUM")
> > data2008<<-merge(exp2008s,fam2008s, by="HHNUM")
> > data2009<<-merge(exp2009s,fam2009s, by="HHNUM")
> > data2010<<-merge(exp2010s,fam2010s, by="HHNUM")
> > data2011<<-merge(exp2011s,fam2011s, by="HHNUM")
> > data2012<<-merge(exp2012s,fam2012s, by="HHNUM")
> > data2013<<-merge(exp2013s,fam2013s, by="HHNUM")
> > data2014<<-merge(exp2014s,fam2014s, by="HHNUM")
> >
> > dput(data2004, file="../dataframes/data2004.txt")
> > dput(data2005, file="../dataframes/data2005.txt")
> > dput(data2006, file="../dataframes/data2006.txt")
> > dput(data2007, file="../dataframes/data2007.txt")
> > dput(data2008, file="../dataframes/data2008.txt")
> > dput(data2009, file="../dataframes/data2009.txt")
> > dput(data2010, file="../dataframes/data2010.txt")
> > dput(data2011, file="../dataframes/data2011.txt")
> > dput(data2012, file="../dataframes/data2012.txt")
> > dput(data2013, file="../dataframes/data2013.txt")
> > dput(data2014, file="../dataframes/data2014.txt")
> >
> >       [[alternative HTML version deleted]]
> >
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