1:10 5:-5 seq(from=23, by=2, length=12) seq(from=10, by=10, length=10) seq(from=10, to=100, by=10) rep(2,10) rep(c(4,5), each=3) # Ten random numbers between 0 and 1 runif(10) # Five random numbers between 100 and 1000 runif(5, 100, 1000) rnorm(10, 100, 10) plot(rnorm(10,100,10)) numbers <- 1:15 sample(numbers, size=15, replace=TRUE) sample(numbers, size=15, replace=FALSE) write.csv(mtcars, "Test-mtcars.csv") read.csv("Test-mtcars.csv") allom <- read.csv("Test-mtcars.csv", header=TRUE) head(allom) head(allom, n=5) tail(allom, n=5) rownames(allom) colnames(allom) write.table(mtcars, "Test-mtcars1.txt") read.table("Test-mtcars1.txt") allom1 <- read.table("Test-mtcars1.txt") head(allom1) head(allom1, n=5) tail(allom1, n=5) rownames(allom1) colnames(allom1) allom1$model <- rownames(allom1) rownames(allom1) <- NULL library(stringr) allom1$maker <- word(allom1$model, 1) allom1 read.table(header=TRUE, text=" a b 1 2 3 4 ") # convert vectros into a dataframe vec1 = c(9,10,1,2,45) vec2 = 1:5 data.frame(x=vec1, y=vec2) # x=y=numbers # data.table(x=vec1, y=vec2) # Error # data.matrix(x=vec1, y=vec) # Error vec3 = c(9,10,1,2,45) vec4 = 1:10 data.frame(x=vec3, y=vec4) # x numbers ars smller than y # vec5 = c(9,10,1,2,45) # vec6 = 1:3 # data.frame(x=vec5, y=vec6) # Error y is smaller than x head(allom1) str(allom1) round(allom1$mpg, digits=1) round(allom1$mpg, digits=-1) allom1$new_mpg <- with(allom1, mpg^2) allom1$new_mpg1 <- allom1$mpg^2 head(allom1) allom1$vs <- NULL head(allom1) summary(allom1) nrow(allom1) ncol(allom1) nums1 <- c(1,4,2,8,11,100,8) nums2 <- c(3.3,8.1,2.5,9.8,21.2,13.8,0.9) nums1[2] nums1[nelements<-length(nums1)] nelements nums1[1:3] nums1[c(1,7,6)] nums1[seq(1,7,by=2)] 1:length(nums2) nums2[sample(1:length(nums2), 5)] length(nums2) nums1[-1] nums1[-c(1, length(nums1))] #logical nums2[nums2>10] nums2[nums2 > 5 & nums2 < 10] nums2[nums2 < 1 | nums2 > 20] nums1[nums1 == 8] # exactly nums1[nums1 != 100] # NOT equal # Subset of nums1, where value is one of 1,4 or 11: # %in% "is an element of" nums1[nums1 %in% c(1,4,11)] # Subset of nums1, where value is NOT 1,4 or 11: nums1[!(nums1 %in% c(1,4,11))] # Where nums1 was 100, make it -100 nums1[nums1 == 100] <- -100 nums1 # Where nums2 was less than 5, make it zero nums2[nums2 < 5] <- 0 nums2

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