DS 413/613 Midterm
1) Using the if-else coding structure demonstrated in class, write a function that will determine if a number is divisible by 3 and 4 If your number is divisible by 3 and 4, the function generates the following statement: this number is divisible by both 3 and 4. If the function is not divisible by both 3 and 4, the function produces a statement that reads: this number is not divisible by both 3 and 4. Test your function by using the numbers 744 and 159.
2) Using r coding methods demonstrated in class, write a function that will produce the difference between the cubes and the squares of the first 5 positive integers. Your output should be given in reverse order. The following number sequence should be produced: 900 648 448 294 180.
3) U <- c(“Maine” , “Texas”, “Delaware”, “Oregon”, “Utah”, “Vermont”, “Ohio”)
a. Is U an atomic vector or a list ?
b. Using R coding, show two methods for extracting/subsetting the element Utah.
c. Use and show R code that will extract all elements except Ohio.
4)V = list(“Chicago”, k = list( 2, 6, 18, 24, 36), FALSE, 13, 1.3, z = 1:20)
a. Is V an atomic vector or a list ? Justify your answer.
b. Use and show R code that will extract the 2nd element of V.
c. Use and show R code that classifies the element FALSE as logical.
5.Copy, paste and run the tribble given below.
tribble( ~John, ~Raymond, ~Martha, ~Alice, ~Juan,
86, 77, 81, 88, 90,
79, 78, 85, 81, 78,
76, 75, 88, 94, 81,
84, 90, 71, 84, 89,
100, 80, 93, 85, 84,
90, 73, 70, 88, 93
) -> TestScores
TestScores
a. Use and show R code (a map function) to find the mean for each column.
b. Use and show R code (a map function) to find the cube of each column element.
c. Use and show R code (a map function) to convert each column value to 100.
6. Use and show R coding that will produce the matrix given below.
[,1] [,2] [,3] [,4]
[1,] 1 4 9 16
[2,] 4 16 36 64
[3,] 9 36 81 144
[4,] 16 64 144 256
7. Use two or three sentences to explain each git command. (Do not run code; you will have that opportunity on the final exam)
a) git clone
b) git init
c) ls
d) git add
e) touch
f) git push -u
g) git commit -m
h) git branch
i) git merge