I am learning R, and instead of learning by rote, I am trying to better understand the language in order to improve my programming. So any "meta-information" on why the following code works would be greatly appreciated...
I obtained this code to extract the first record from each of a series of vectors in a list: >example<- list(c(1,2),c(3,4),c(4,5)) [[1]] [1] 1 2 [[2]] [1] 3 4 [[3]] [1] 4 5 >sapply(example,'[',1) [1] 1 3 4 however, after perusing my book and the interweb, i remain puzzled about how '[' works as a function in sapply. -Why does R recognize '[' as a function? -Why does it need the quotes? - How does the function know to use the optional(?) argument "1" as the index location? - Any other information linking this specific example to the broader R environment? Any explanation of how this function works will be a small incremental gain in my understanding of R, so thanks in advance. Chipper -- View this message in context: http://r.789695.n4.nabble.com/Using-as-a-function-tp2307292p2307292.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
