You definitely need to learn about the differences between R and the other languages that you are familiar with. You've done some work since you mention the apply() family, but those are just another way of programming a loop. In many cases (including this one), a loop is not needed. Here's your code in a plain text message with some additions:
data <- data.frame(x = c(1,2,3,1,1,1), y = c(1,2,3,4,6,7)) # fin_hyp could just as easily be a data frame or a matrix fin_hyp <- list(slope = 2, constant = 1) # R vectorizes the following command and automatically computes the # result for each row in "data" outputs <- data['y'] > fin_hyp['slope'] * data['x'] + fin_hyp['constant'] outputs # Add a plot showing points above and below the line # ifelse is vectorized so it creates a vector with # 16 (symbol for solid circle) if above the line and # 1 (open circle) if below the line sym <- ifelse(outputs, 16, 1) plot(y~x, data, pch=sym) abline(a=fin_hyp$constant, b=fin_hyp$slope) David L. Carlson Department of Anthropology Texas A&M University -----Original Message----- From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Duncan Murdoch Sent: Friday, November 13, 2015 1:16 PM To: Ilgaz S <ilgaz.so...@gmail.com>; r-help@r-project.org Subject: Re: [R] Suprising R behaviour On 13/11/2015 8:11 AM, Ilgaz S wrote: > Hello everybody, I am new to R and I discovered something that suprise me > and I have a question about it. > Today I wanted to return a bit array which represents this: > > if( arbitrary point above the line) > return TRUE > else > return FALSE > > First I tought I would use for loop and access every element of the data. > Then I tend to use lapply function. > > At the end, I accidently done that without using any if/else statement. ( > or for loop ) Here is the code: I can't read your code (you posted in HTML, don't do that), but it sounds as though you have discovered vectorized operations. These are central to good R programming, and are well described in the Introduction to R manual. Duncan Murdoch > > data <- data.frame(x= c(1,2,3,1,1,1), y = c(1,2,3,4,6,7))fin_hyp <- > list(slope=2,constant=1)outputs <- data['y'] > fin_hyp['slope'] * > data['x'] +fin_hyp['constant']outputs > > What is R doing here? It is using loop somewhere inside? Is this code > more efficient than other methods I mentioned? > > Thank you, I.S. > > [[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. ______________________________________________ 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. ______________________________________________ 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.
