Can anyone tell me what is skip=2, skip =7 and %in% mean here? fromcsv=read.csv ('2_2005_top200_postdoc.csv',header=FALSE,skip=7,stringsAsFactors=FALSE) fromreadxls = read.xls ('2_2005_top200_postdoc.xls',stringsAsFactors=FALSE,header=FALSE,skip=2) fromreadxls = fromreadxls[fromreadxls$V7 %in% c('Public','Private'),] Thanks!