# ZAD1 & ZAD2
x <- c(rep(TRUE, 3), rep(FALSE, 4), rep(TRUE, 2), rep(FALSE, 5))
y <- as.numeric(x)

#ZAD3
z <- c(seq(1, 20, by=1), rep(0, 10), seq(2, 40, by=2))
z <- c(z, rev(z))
print(z)

#ZAD4
print(letters[25])

#ZAD5
zad5 <- 1:1000
for(i in 1:length(zad5)){
  if (zad5[i]%%2==0){
    zad5[i]=1/zad5[i]
  }
}
print(zad5)

#ZAD6
zad6 <- c(6, 3, 4, 5, 2, 3)
print(zad6[order(zad6, decreasing = TRUE)])

#ZAD7
zad7 <- c(-1.876, -1.123, -0.123, 0, 0.123, 1.123, 1.876)
znak <- vector()
zaok <- vector()
calk <- vector()
for (x in zad7){
  zaok <- c(zaok, round(x, digits=2))
  calk <- c(calk, floor(x))
  if (x<0){
    znak <- c(znak, -1)
  } else if (x>0){
    znak <- c(znak, 1)
  } else {
    znak <- c(znak, 0)
  }
}
print(znak)
print(zaok)
print(calk)

#ZAD8
start <- Sys.time()
for (x in 1:100000000){
  pierw <- sqrt(x)
}
print(Sys.time() - start)

start <- Sys.time()
for (x in 1:100000000){
  pierw <- x^(1/2)
}
print(Sys.time() - start)


#ZAD9
install.packages("schoolmath")
library(schoolmath)

last <- 0
number <- 0
for (x in primlist){
  if (x >= 1000){
    print(last)
    break
  }
  last <-x
  if (x > 100 && x < 500){
    number <- number + 1
  }
}
print(number)


# ZAD 10
print(c(paste(paste(rep("a", 3), 1:3, sep = "")), paste(paste(rep("b", 3), 1:3, sep = ""))))


#ZAD 11
litery <- c("X", "Y", "Z")
print(paste(1:30, rep(litery, 10), sep="."))


#ZAD 12
install.packages("car")
library(car)

odpowiedzi <- c("a", "b", "c", "d", "e")
x <- sample(odpowiedzi, 100, replace = TRUE)
print(recode(x, "c('a', 'b') = 1; c('c', 'd') = 2; 'e' = 3"))