Why is “L” used as a suffix? I’ve never seen it written down, but I theorise in short for two reasons: Because R handles complex numbers which may be specified using the suffix “i” and this would be too simillar to “I” Because R’s integers are 32-bit long integers and “L” therefore appears to be … Read more
There are R functions that automatically take sensible approaches to the “equality problem”: > (3 – 2.9) <=0.1 #[1] FALSE > all.equal( (3 – 2.9) , 0.1) #[1] TRUE It uses the sqrt of R’s smallest positive floating point number as its default threshold, so it handles multiplications and division propagated errors. Ends up being … Read more
Maybe not the most simple answer, but this will work: paste(sort(unlist(strsplit(s, “”))), collapse = “”) Or modify the strReverse function that is defined in the help page for ?strsplit to suit our needs. We’ll call it strSort: strSort <- function(x) sapply(lapply(strsplit(x, NULL), sort), paste, collapse=””)
First, note that the reason ggplot doesn’t encourage this is because the plots tend to be difficult to interpret. You can get your two color gradient scales, by resorting to a bit of a cheat. In geom_point certain shapes (21 to 25) can have both a fill and a color. You can exploit that to … Read more
No, but you can write it yourself: q <- function(…) { sapply(match.call()[-1], deparse) } And just to show it works: > q(a, b, c) [1] “a” “b” “c”
My favourite use of mapply: Example Data a <- data.frame(a=runif(5), b=runif(5)) > a a b 1 0.8403348 0.1579255 2 0.4759767 0.8182902 3 0.8091875 0.1080651 4 0.9846333 0.7035959 5 0.2153991 0.8744136 and b b <- data.frame(c=runif(5), d=runif(5)) > b c d 1 0.7604137 0.9753853 2 0.7553924 0.1210260 3 0.7315970 0.6196829 4 0.5619395 0.1120331 5 0.5711995 0.7252631 … Read more
It is not a good idea to compare apples to oranges, as PCRE regex can do much more than TRE regex enine. Although they share similar constructs, even then appearances might turn out deceitful. What is similar between TRE and PCRE TRE supports literals as PCRE. A literal is either an ordinary character, an 8-bit … Read more
There’s the intToBits function that converts any integer to a vector of 32 raws, so you can do this: decimals <- c(3,5,11,4) m <- sapply(decimals,function(x){ as.integer(intToBits(x))}) m > m [,1] [,2] [,3] [,4] [1,] 1 1 1 0 [2,] 1 0 1 0 [3,] 0 1 0 1 [4,] 0 0 1 0 [5,] 0 … Read more
The levels should be specified explicitly: A$animal <- factor(A$animal, levels = c(“dog”, “elephant”,”cat”)) A$color <- factor(A$color, levels = c(“green”, “blue”, “red”)) Then you order by the 2 columns simultaneously: A[order(A$animal,A$color),] # animal color # 6 dog green # 4 dog blue # 5 dog red # 9 elephant green # 7 elephant blue # 8 … Read more
Here’s one way with ave: ave(df$a, cumsum(c(F, diff(df$a) < 0)), FUN=seq_along) – 1 [1] 0 1 2 3 0 1 2 3 4 5 6 0 1 0 We can get a running count grouped by diff(df$a) < 0. Which are the positions in the vector that are less than their predecessors. We add c(F, … Read more