Hi Bert, Thank you so much for your help. However I don't really sure what is the use of y values. Can we do without it?
x <- as.character(FKASA$STUDENT_ID) y <- c(1,786) My.Data <- data.frame (x,y) My.Data[grep("^AA14", My.Data$x), ] I got the following data: x y 1 AA14068 1 7 AA14090 1 11 AA14099 1 14 AA14012 786 15 AA14039 1 22 AA14251 786 On Mon, Mar 13, 2017 at 11:51 AM, Bert Gunter <bgunter.4...@gmail.com> wrote: > 1. Your code is incorrect. All entries are character strings and must be > quoted. > > 2. See ?grep and note in particular (in the "Value" section): > > "grep(value = TRUE) returns a character vector containing the selected > elements of x (after coercion, preserving names but no other > attributes)." > > > 3. While the fixed = TRUE option will work here, you may wish to learn > about "regular expressions", which can come in very handy for > character string manipulation tasks. ?regex in R has a terse, but I > have found comprehensible, discussion. There are many good gentler > tutorials on the web, also. > > > Cheers, > Bert > > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Sun, Mar 12, 2017 at 8:32 PM, roslinazairimah zakaria > <roslina...@gmail.com> wrote: > > Dear r-users, > > > > I have this list of student ID, > > > > dt <- c(AA14068, AA13194, AE11054, AA12251, AA13228, AA13286, AA14090, > > AA13256, AA13260, AA13291, AA14099, AA15071, AA13143, AA14012, AA14039, > > AA15018, AA13234, AA13149, AA13282, AA13218) > > > > and I would like to extract all student of ID AA14... only. > > > > I search and tried substrt, subset and select but it fail. > > > > substr(FKASA$STUDENT_ID, 2, nchar(string1)) > > Error in nchar(string1) : 'nchar()' requires a character vector > >> subset(FKASA, STUDENT_ID=="AA14" ) > > [1] FAC_CODE FACULTY STUDENT_ID NAME PROGRAM KURSUS > > CGPA ACT_SS ACT_VAL ACT_CS ACT_LED ACT_PS > > ACT_IM > > [14] ACT_ENT ACT_CRE ACT_UNI ACT_VOL... > > > > Thank you so much for your help. > > > > How do I do it? > > -- > > *Roslinazairimah Zakaria* > > *Tel: +609-5492370; Fax. No.+609-5492766* > > > > *Email: roslinazairi...@ump.edu.my <roslinazairi...@ump.edu.my>; > > roslina...@gmail.com <roslina...@gmail.com>* > > Faculty of Industrial Sciences & Technology > > University Malaysia Pahang > > Lebuhraya Tun Razak, 26300 Gambang, Pahang, Malaysia > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > 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. > -- *Roslinazairimah Zakaria* *Tel: +609-5492370; Fax. No.+609-5492766* *Email: roslinazairi...@ump.edu.my <roslinazairi...@ump.edu.my>; roslina...@gmail.com <roslina...@gmail.com>* Faculty of Industrial Sciences & Technology University Malaysia Pahang Lebuhraya Tun Razak, 26300 Gambang, Pahang, Malaysia [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.