[R] Question about Calculation of Cross Product

The function of crossprod in R puzzled me. I would like to calculate the cross product of two vectors. According to my text book, it defines like this: a = (ax, ay, az) b = (bx, by, bz) then, the cross product of a and b is: a X b = (ay*bz-az*by, az*bx-ax*bz, ax*by-ay*bz) It can also write in a de

[R] help about R basic

This is my first time to ask for help in the R mailing list, so sorry for my misbehavior. The question is actually an example of the apply function embedded in R. Code is here: > x <- cbind(x1 = 3, x2 = c(4:1, 2:5)) > dimnames(x)[[1]] <- letters[1:8] > x > x1 x2 a 3 4 b 3 3 c 3 2 d 3

[R] Question about syntax in lm function

I encounters some codes in ggplot2 manual and confused with one of its lm syntax. The code is here: library(ggplot2) d <- subset(diamonds, carat < 2.5 & rbinom(nrow(diamonds), 1, 0.2) == 1) d$lcarat <- log10(d$carat) d$lprice <- log10(d$price) detrend <- lm(lprice ~ lcarat, data = d) d$lprice2