R Notes
Table of Contents
Vectors
c is for combine
sentence <- c("this", "is", "a", "sentence") sentence # [1] "this" "is" "a" "sentence"
First index is 1, not 0
sentence[1] # "this"
Overwriting
sentence[4] <- "silly" sentence # [1] "this" "is" "a" "silly"
Appending
sentence[5] <- "example" sentence # [1] "this" "is" "a" "silly" "example"
Getting multiple elements
sentence[c(1, 5)] # [1] "this" "example"
Ranges
sentence[4:5] # [1] "silly" "example" sentence[4:5] <- c("cool", "language") # [1] "this" "is" "a" "cool" "language"
Sequences
5:9 == seq(5, 9) # [1] TRUE TRUE TRUE TRUE TRUE
With a step
seq(2, 8, 2) # [1] 2 4 6 8
Named elements
named <- 1:3 names(named) <- c("this", "that", "the other") named # this that the other # 1 2 3 named["the other"] <- 42 named["the other"] == named[3] # T named[3] == 42 # T
Combining
sails <- c(1:10,5:1,1:30,15:1,1:20,10:1)
barplot(sails)
Basic arithmetic
misfits <- c(1, 3, 8) # [1] 1 3 8 misfits + 10 # [1] 11 13 18 misfits - 10 # [1] -9 -7 -2 misfits * 10 # [1] 10 30 80 misfits / 10 # [1] 0.1 0.3 0.8
Sort of like Clojure's map.
(for [f [+ - * /]] (map #(f % 10) '(1 3 8)))
Keep in mind, it doesn't alter the original variable.
misfits # [1] 1 3 8
Scatter plots
x <-
na.rm
a <- c(1, NA, 2, NA, 3) # [1] 1 NA 2 NA 3 sum(a) # [1] NA sum(a, na.rm = TRUE) # [1] 6