[R] apply fn to many dataframes

markleeds at verizon.net markleeds at verizon.net
Tue May 26 01:03:56 CEST 2009

   Hi:Â  you have to return the dataframe inside the lapply. I also changed =
   to <- but I doubt that matters.
   d1 <- data.frame(x1=1,x3=4)
   d2 <- data.frame(x1=2,x3=5)
   d3 <- data.frame(x1=3,x3=6)
   d4 <- data.frame(x1=4,x3=7)
   a = list(d1,d2,d3,d4)
   lapply(a,function(.df) {
   Â Â Â  names(.df)[2] <- "x2"
   Â Â Â  .df

   On May 25, 2009, James Fearon <jfearon at stanford.edu> wrote:

     Say I have dataframes d1, d2, ... , dn, and I want to apply a
     function to all of them. For example, say I want to change the name
     of the second variable in each dataframe to "x2". The following doesn't
     a = list(d1,d2,d3,d4)
     lapply(a,function(x) names(x)[2] = "x2")
     What would work?
     Thanks for any help.
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     and provide commented, minimal, self-contained, reproducible code.


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