Hi Uwe! 2011/10/20 Uwe Ligges <ligges at statistik.tu-dortmund.de>: > names.arg = rep(NA, nrow(file.codes)) Yes, that works beautifully. Danke schoen! Henri-Paul -- Henri-Paul Indiogine Curriculum & Instruction Texas A&M University TutorFind Learning Centre Email: hindiogine at gmail.com Skype: hindiogine Website: http://people.cehd.tamu.edu/~sindiogine