Hi, Assuming that this is the case: v2 <- c("g_", "", "g2","g3") which(v2=="") #[1] 2
##Second question v1 <- c("g_", "g_w1", "g_w2", "g_bc3") grepl("\\bg_\\b",v1) #[1] TRUE FALSE FALSE FALSE v1[grepl("\\bg_\\b",v1)] #[1] "g_" A.K. Hi, I have a vector with the name of an element that is empty. How can I find out the index of this element? The following doesn't work: empty.char = grep('[:blank:||:space:]' ,names(v)) if (length(empty.char)>0) .... How about if the name of one element is g_ and the name of other elements g_anyword where any word contain alphanumeric characters and I want to find the one whose name contain only g_? Cheers, Carol ______________________________________________ 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.