You are also missing the fact that loops are often not required in R. In this case print() has a method for printing data frames and that method is automatically used when you simply type the data.frame name or if you explicitly call it with print(stockList):
> stockList <- read.table(text="symbol,shares + XOM,1000 + APA,400 + CVX,200", header = T, sep=",") > > stockList symbol shares 1 XOM 1000 2 APA 400 3 CVX 200 You will save yourself hours of frustration by reading some of the official and unofficial documentation for R: http://cran.r-project.org/manuals.html http://www.r-project.org/other-docs.html http://cran.r-project.org/other-docs.html David Carlson -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of David Winsemius Sent: Sunday, June 29, 2014 5:58 PM To: Robert Sherry Cc: r-help@r-project.org Subject: Re: [R] A Question about read.table and Data Frames in R On Jun 29, 2014, at 3:22 PM, Robert Sherry wrote: > I created the following file: > > symbol,shares > XOM,1000 > APA,400 > CVX,200 > > I then read the file in R using the command: > stockList=read.table("/NotesOnR/stockList", header = T, sep=",") > > I would then expect the following expression to evaluate to the simple > string APA: > stockList$symbol[2] > However when I type that in on the command line, I get: > [1] APA > Levels: APA CVX XOM > > I would also expect to be able to print out the table by using the > command: > for( i in 1:3 ) { > print( stockList$symbol[i] ) > print ( stockList$shares[i] ) > } > > However, as part of the output I get: > Levels: APA CVX XOM > I do not understand what is going on. Also, when I try passing the > expression stockList$symbol to a standard function in R, it does not > work. > > I think that I am missing something here but I am not sure what I am > missing. You are missing the fact that a factor variable was created. If you had added stringsAsFactors=FALSE to your read.table code, you would ahve gotten what you expected. > Should I be writing code like: > for ( i in stockList$smybol ) > However, given the symbol, I am not sure how to get the share count > that is > in the same row. > > I thank the group in advance for their responses. > > Bob > > ______________________________________________ > 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. David Winsemius, MD Alameda, CA, USA ______________________________________________ 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. ______________________________________________ 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.
