exercise_10_3.R

#Question A
loopvec1 <- 5:7
loopvec2 <- 9:6
foo <- matrix(NA, length(loopvec1), length(loopvec2))

for(i in 1:length(loopvec1)) {
    foo[i,] <- loopvec1[i] * loopvec2
  }

#Question B
chars <- c("Peter","Homer","Lois","Stewie","Maggie","Bart")
num_vals <- rep(NA, times=length(chars))

for (i in 1:length(chars)) {
  num_vals[i] <- switch(EXPR=chars[i],Homer=12,Marge=34,Bart=56,Lisa=78,Maggie=90,NA)
}

#Question C
#i
mylist <- list(
  aa=c(3.4, 1), bb=matrix(1:4, 2, 2), 
  cc=matrix(c(T, T, F, T, F, F), 3, 2),
  dd="string here",
  ee=list(c("hello", "you"), matrix(c("hello", "there"))),
  ff=matrix(c("red", "green", "blue", "yellow"))
)

#ii
mylist <- list("tricked you", as.vector(matrix(1:6, 3, 2)))

#iii
mylist <- list(
  list(1,2,3), list(c(3,2), 2),
  list(c(1, 2), matrix(c(1,2))),
  rbind(1:10, 100:91)
)

matrix_count <- 0

for (member in mylist) {
  if (is.matrix(member)) {
    matrix_count <- matrix_count + 1
  } else if (is.list(member)) {
    for (submember in member) {
      if (is.matrix(submember)) {
        matrix_count <- matrix_count + 1
      }
    }
  }
}