Hi, Try: my.data <- structure(list(column_1 = 1:32, column_2 = structure(c(1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8), .Label = c("Unstimulated", "ESAT6", "CFP10", "Rv3615c", "Rv2654", "Rv3879", "Rv3873", "PHA"), class = "factor"), column_3= structure(c(1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4), .Label = c("bd", "2m", "1m", "0.5m"), class = "factor"), column_4 = structure(c(71.62097178, 2.892223468, 144.8618621, 40.90079262, 37.0516856, 32.78206822, 72.44424152, 1512.516293, 3164.748333, 1092.634557, 28733.20269, 1207.87783, 729.6090973, 151.8706088, 241.2466141, 9600.963594, 682.865522, 5869.375226, 554.8924896, 2982.759858, 7690.028092, 40.37298719, 942.3549279, 3403.679967, 103.9862389, 35.28562613, 321.5985377, 0.274424607, 3352.874906, 93.76421187, 21.3709382, 4193.183281))), .Names = c("row", "stimulation", "type", "copy"), row.names= c(NA,-32L), class = "data.frame")
str(my.data) 'data.frame': 32 obs. of 4 variables: $ row : int 1 2 3 4 5 6 7 8 9 10 ... $ stimulation: Factor w/ 8 levels "Unstimulated",..: 1 2 3 4 5 6 7 8 1 2 ... $ type : Factor w/ 4 levels "bd","2m","1m",..: 1 1 1 1 1 1 1 1 2 2 ... $ copy : num 71.62 2.89 144.86 40.9 37.05 ... A.K. dear all, I have tried to create a dataframe using the structure() function, but it did not really work. In column 1 i have the row number, in column 2 and 3 factors (8 and 4 levels respectively) and in column 4 the actual data. any clue on what went wrong? best regards luigi my.data<-structure(list( column_1 = 1:32, column_2 = structure(c(1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8), .Label = c("Unstimulated", "ESAT6", "CFP10", "Rv3615c", "Rv2654", "Rv3879", "Rv3873", "PHA"), class = "factor"), column_3 = structure(c(1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4), .Label = c("bd", "2m", "1m", "0.5m"), class = "factor"), column_4 = c(71.62097178, 2.892223468, 144.8618621, 40.90079262, 37.0516856, 32.78206822, 72.44424152, 1512.516293, 3164.748333, 1092.634557, 28733.20269, 1207.87783, 729.6090973, 151.8706088, 241.2466141, 9600.963594, 682.865522, 5869.375226, 554.8924896, 2982.759858, 7690.028092, 40.37298719, 942.3549279, 3403.679967, 103.9862389, 35.28562613, 321.5985377, 0.274424607, 3352.874906, 93.76421187, 21.3709382, 4193.183281), .Names = c("row", "stimulation", "type", "copy"), class = "data.frame")) attach(my.data) ______________________________________________ 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.