Hi, Try: df1$CatEch<-paste0(df1[,1],".",sprintf("%02d",df1[,2])) identical(df1,df2) #[1] TRUE A.K.
----- Original Message ----- From: Arnaud Michel <michel.arn...@cirad.fr> To: R help <r-help@r-project.org> Cc: Sent: Sunday, September 8, 2013 12:22 PM Subject: [R] to avoid a do loop Hello I have a large dataframe (nrow=55000). This below df1 an extract of the original dataframe dput(df1) structure(list(Cat = c(6, 6, 6, 6, 6, 6, 6, 6, 4, 4, 4, 4, 4, 4, 8, 8, 9, 9, 9, 9, 9, 9, 9, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 2, 2, 2, 2, 2, 2, 6, 7, 7, 7, 7, 7), Ech = c(8, 9, 10, 11, 12, 12, 13, 13, 11, 12, 13, 14, 14, 14, 9, 10, 5, 6, 7, 7, 7, 7, 7, 7, 8, 9, 10, 11, 11, 11, 4, 5, 6, 7, 8, 8, 8, 9, 9, 8, 9, 2, 3, 4, 5, 5, 5, 5, 5, 5, 5, 5, 1, 2, 3, 4, 5, 6, 6, 6, 7, 7, 7, 5, 6, 7, 8, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 15, 5, 6, 7, 7, 8, 8, 8, 8, 9, 9, 13, 13, 14, 15, 15, 15, 10, 1, 2, 3, 4, 5)), .Names = c("Cat", "Ech" ), row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "10", "11", "12", "13", "14", "15", "17", "18", "19", "20", "21", "22", "23", "24", "25", "27", "28", "29", "30", "31", "32", "33", "35", "36", "37", "38", "39", "40", "41", "42", "43", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "59", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "71", "72", "73", "74", "75", "76", "77", "78", "79", "80", "81", "82", "83", "84", "86", "87", "88", "89", "90", "91", "92", "93", "94", "95", "96", "98", "99", "100", "101", "102", "103", "105", "106", "107", "108", "109", "110"), class = "data.frame") I do not manage to avoid a do loop because very slow I want to obtain a new dataframe df2 with a new variable CatEch. CatEch is the paste of the 2 variables Cat and Ech dput(df2) structure(list(Cat = c(6, 6, 6, 6, 6, 6, 6, 6, 4, 4, 4, 4, 4, 4, 8, 8, 9, 9, 9, 9, 9, 9, 9, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 2, 2, 2, 2, 2, 2, 6, 7, 7, 7, 7, 7), Ech = c(8, 9, 10, 11, 12, 12, 13, 13, 11, 12, 13, 14, 14, 14, 9, 10, 5, 6, 7, 7, 7, 7, 7, 7, 8, 9, 10, 11, 11, 11, 4, 5, 6, 7, 8, 8, 8, 9, 9, 8, 9, 2, 3, 4, 5, 5, 5, 5, 5, 5, 5, 5, 1, 2, 3, 4, 5, 6, 6, 6, 7, 7, 7, 5, 6, 7, 8, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 15, 5, 6, 7, 7, 8, 8, 8, 8, 9, 9, 13, 13, 14, 15, 15, 15, 10, 1, 2, 3, 4, 5), CatEch = c("6.08", "6.09", "6.10", "6.11", "6.12", "6.12", "6.13", "6.13", "4.11", "4.12", "4.13", "4.14", "4.14", "4.14", "8.09", "8.10", "9.05", "9.06", "9.07", "9.07", "9.07", "9.07", "9.07", "6.07", "6.08", "6.09", "6.10", "6.11", "6.11", "6.11", "7.04", "7.05", "7.06", "7.07", "7.08", "7.08", "7.08", "7.09", "7.09", "7.08", "7.09", "8.02", "8.03", "8.04", "8.05", "8.05", "8.05", "8.05", "8.05", "8.05", "8.05", "8.05", "8.01", "8.02", "8.03", "8.04", "8.05", "8.06", "8.06", "8.06", "8.07", "8.07", "8.07", "6.05", "6.06", "6.07", "6.08", "6.09", "6.09", "6.10", "6.10", "6.11", "6.11", "6.11", "6.11", "6.11", "6.11", "7.15", "8.05", "8.06", "8.07", "8.07", "8.08", "8.08", "8.08", "8.08", "8.09", "8.09", "2.13", "2.13", "2.14", "2.15", "2.15", "2.15", "6.10", "7.01", "7.02", "7.03", "7.04", "7.05")), .Names = c("Cat", "Ech", "CatEch"), row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "10", "11", "12", "13", "14", "15", "17", "18", "19", "20", "21", "22", "23", "24", "25", "27", "28", "29", "30", "31", "32", "33", "35", "36", "37", "38", "39", "40", "41", "42", "43", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "59", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "71", "72", "73", "74", "75", "76", "77", "78", "79", "80", "81", "82", "83", "84", "86", "87", "88", "89", "90", "91", "92", "93", "94", "95", "96", "98", "99", "100", "101", "102", "103", "105", "106", "107", "108", "109", "110"), class = "data.frame") Any idea ? -- Michel ARNAUD Chargé de mission auprès du DRH DGDRD-Drh - TA 174/04 Av Agropolis 34398 Montpellier cedex 5 tel : 04.67.61.75.38 fax : 04.67.61.57.87 port: 06.47.43.55.31 ______________________________________________ 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. ______________________________________________ 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.