#1/2 m = rnorm(10, 3, 2) m mean(m) sd(m) #1/3 z = airquality head(z,4) tail(z,4) ?head #1/4 x = c(1.5, 0.6) class(x) x = c(TRUE, FALSE) class(x) x = c(T, F) class(x) x = c("a", "b", "c", "d") class(x) x = 9:29 class(x) x = c(9:29) class(x) x = c(1.7, "a") class(x) x = c(TRUE,2) class(x) x = c("a", TRUE) class(x) #b x = c(1,a) #c as.logical(c(0.5, 0.6)) as.logical(c(0, 1+2i)) as.logical(c("a", "b", "c")) as.logical(c(0.5, "aa")) #5 matrix = rbind(5:8, 15:12) #7 nrow(airquality) ncol(airquality) names(airquality) head(airquality) names(airquality) = c("Ozon", "Sugarzas", "Szel", "Homerseklet", "Honap", "Nap") head(airquality) #8 v = c(1,5,6,2,8,7) v[5:6] v[c(3,5,6)] matrix[,3] matrix[,3,drop = F] #1/9ab airquality[2,] new_airquality = airquality[,c(1,2,5,6)] #1/9c airquality[17, ][,1] airquality[17,1] airquality$Ozone[17] airquality[17,]$Ozone #1/9d airquality[!is.na(airquality$Ozone),] nrow(airquality[!is.na(airquality$Ozone),]) sum(!is.na(airquality$Ozone)) #1/9e jo_ozone <- airquality[!is.na(airquality$Ozone),] mean(jo_ozone$Solar.R, na.rm = TRUE) #1/10/b max_Solar.R <- max(airquality$Solar.R, na.rm = TRUE) subset(airquality, airquality$Solar.R == max_Solar.R, select = c(Month, Day)) #2/1d,e adat <- read.csv("http://www.cs.bme.hu/dm/001.csv") nrow(adat) ncol(adat) str(adat) head(adat) #2/1f jo_sorok <- complete.cases(adat) nrow(adat[jo_sorok, ]) #2/2 weboldal <- readLines("http://www.cs.bme.hu/szeminarium") length(weboldal) weboldal[95]