Perhaps this will help. Jean
df <- structure(list(Left = c(9L, 4L, 2L, 6L, 3L, 4L, 3L, 4L, 10L, 9L), Right = c(8L, 3L, 1L, 5L, 1L, 1L, 2L, 2L, 8L, 10L)), .Names = c("Left", "Right"), class = "data.frame", row.names = 1:10) lookup <- structure(list(input = c(5L, 10L, 4L, 8L, 6L, 5L, 7L, 2L, 9L, 10L, 2L), output = c(1L, 1L, 2L, 3L, 5L, 6L, 6L, 7L, 7L, 7L, 8L)), .Names = c("input", "output"), class = "data.frame", row.names = 1:10) df2 <- merge(df, lookup, by.x="Left", by.y="input", all.x=TRUE) names(df2)[names(df2)=="output"] <- "Leftout" df3 <- merge(df2, lookup, by.x="Right", by.y="input", all.x=TRUE) names(df3)[names(df3)=="output"] <- "Rightout" Right Left Leftout Rightout 1 1 2 7 NA 2 1 2 8 NA 3 1 3 NA NA 4 1 4 2 NA 5 2 3 NA 7 6 2 3 NA 8 7 2 4 2 7 8 2 4 2 8 9 3 4 2 NA 10 5 6 5 6 11 5 6 5 1 12 8 9 7 3 13 8 10 1 3 14 8 10 7 3 15 10 9 7 1 16 10 9 7 7 On Thu, Jul 25, 2013 at 10:13 AM, Juan Antonio Balbuena <j.a.balbu...@uv.es>wrote: > > Hello > I hope that there is a simple solution to this apparently complex > problem. > Any help will be much appreciated: > I have a dataframe with Left and Right readings (that is, elements in > each > row are paired). For instance, > Left Right > [1] 9 8 > [2] 4 3 > [3] 2 1 > [4] 6 5 > [5] 3 1 > [6] 4 1 > [7] 3 2 > [8] 4 2 > [9] 10 8 > [10] 9 10 > I need to produce a new data frame where the values are transformed > according to a look-up table such as > input output > [1] 5 1 > [2] 10 1 > [3] 4 2 > [4] 8 3 > [5] 6 5 > [6] 5 6 > [7] 7 6 > [8] 2 7 > [9] 9 7 > [10] 10 7 > [11] 2 8 > So [1, ] in the new dataframe would be 7 3. Quite simple so far, but > what > makes things complicated is the multiple outputs for a single input. In > this > example, 10 corresponds to 1 and 7 so [9, ] in the input dataframe must > yield two rows in its output counterpart: 1 3 and 7 3. Likewise the > output > for [10, ] should be 7 1 and 7 7. In addition, given that 3 and 1 are > missing as inputs the output for [5, ] should be NA NA. > Thank you very much for your time. > Juan Antonio Balbuena > > -- > > Dr. Juan A. Balbuena > Marine Zoology Unit > Cavanilles Institute of Biodiversity and Evolutionary Biology > University of > Valencia > [1]http://www.uv.es/~balbuena > P.O. Box 22085 > [2]http://www.uv.es/cavanilles/zoomarin/index.htm > 46071 Valencia, Spain > [3]http://cetus.uv.es/mullpardb/index.html > e-mail: [4]j.a.balbu...@uv.es tel. +34 963 543 658 fax +34 963 > 543 733 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > NOTE! For shipments by EXPRESS COURIER use the following street address: > C/ Catedrático José Beltrán 2, 46980 Paterna (Valencia), Spain. > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > References > > 1. http://www.uv.es/%7Ebalbuena > 2. http://www.uv.es/cavanilles/zoomarin/index.htm > 3. http://cetus.uv.es/mullpardb/index.html > 4. mailto:j.a.balbu...@uv.es > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.