Figure out why gather() is so much slower than melt() #18

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1. hadley commented on Aug 22, 2014

   

   hadley

   on Aug 22, 2014

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   Looks like it's the non-standard eval:

   library(microbenchmark)
   iris1 <- iris[sample(1:nrow(iris), 1e4, replace = T), ] 
   
   microbenchmark(
     melt = reshape2::melt(iris1,id.vars="Species"), 
     gather = tidyr::gather(iris1, variable, value, -Species),
     gather_ = tidyr::gather_(iris1, quote(variable), quote(value), c("Sepal.Length", "Sepal.Width", "Petal.Length", "Petal.Width"))
   )

   Unit: milliseconds
       expr  min   lq median   uq   max neval
       melt 2.41 2.66   3.15 4.87 52.49   100
     gather 3.97 4.98   6.40 6.82  8.41   100
    gather_ 2.43 2.67   3.07 4.94 51.42   100
   
2. hadley

   closed this as completedin eb5fff7on Aug 22, 2014