Homework 2

Computing in Molecular Biology 1 – Molecular Biology and Genetics Department

Please download the answer file and edit it on Rstudio. Write your student number in the correct place at the beginning of the answer file. You should be able to Knit HTML and get the same results as the document you have in paper. Please do Knit often and verify that your document has no errors. If your document does not Knit, you will not have full grade.

When you finish, send the answers.Rmd file to my mailbox (andres.aravena+cmb@istanbul.edu.tr). Be sure to use the correct email address and send only one file.

IMPORTANT: Write your student number in the correct place at the beginning of the answer file.

1 Using R

1.1 Write the R command to make a vector with 30 even numbers starting from 6

 [1]  6  8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50
[24] 52 54 56 58 60 62 64

# write your answer here

1.2 Write the R command to make a vector with 20 copies of the number 9

 [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
[36] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

# write your answer here

1.3 Write the R command to produce this vector

[1] "x" "y" "y" "z" "z" "z"

# write your answer here

1.4 Write the R command to produce this vector

[1] red   white black blue  brown
Levels: black blue brown red white

# write your answer here

1.5 Write the R command to create a logic vector, which is TRUE for the elements of state.area that are greater than 5E4

 [1]  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE FALSE  TRUE  TRUE FALSE
[12]  TRUE  TRUE FALSE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE
[23]  TRUE FALSE  TRUE  TRUE  TRUE  TRUE FALSE FALSE  TRUE FALSE  TRUE
[34]  TRUE FALSE  TRUE  TRUE FALSE FALSE FALSE  TRUE FALSE  TRUE  TRUE
[45] FALSE FALSE  TRUE FALSE  TRUE  TRUE

# write your answer here

2 Using indices

2.1 Show the first 4 elements of the vector state.abb

[1] "AL" "AK" "AZ" "AR"

# write your answer here

2.2 Show all the elements of the vector state.abb, except the first 40

 [1] "SD" "TN" "TX" "UT" "VT" "VA" "WA" "WV" "WI" "WY"

# write your answer here

2.3 Show the elements of the vector state.name corresponding to states whose area is greater than 2E5

[1] "Alaska" "Texas" 

# write your answer here

2.4 Create a vector with the values 1, 2, 3, and 4, and with names “one”, “two”, “three”, and “four”.

Assign this vector to the variable x. Then show the content of x

  one   two three  four 
    1     2     3     4 

# write your answer here

2.5 Using the name as index, show the value of two in the vextor x

two 
  2 

# write your answer here

3 About Computing

Please provide an original answer the following questions, using your own words. All answers should be personal and original.

3.1 What is a computer? what are computers useful for?

REPLACE THIS WITH YOUR ANSWER

3.2 What are the parts of a computer?

REPLACE THIS WITH YOUR ANSWER

3.3 How do computers represent information?

REPLACE THIS WITH YOUR ANSWER

3.4 What is a prompt? What is the interpretation?

REPLACE THIS WITH YOUR ANSWER

3.5 Can you use Microsoft Word for scientific computing?

REPLACE THIS WITH YOUR ANSWER

3.6 What are the advantages of Markdown as a way to represent documents?

REPLACE THIS WITH YOUR ANSWER

4 About R

Please answer the following questions:

4.1 Which are the basic data types in R?

REPLACE THIS WITH YOUR ANSWER

4.2 What is the meaning of NA? Why it is useful?

REPLACE THIS WITH YOUR ANSWER

4.3 What types of data can be used as indices of vectors in R? What are the advantages of each one?

REPLACE THIS WITH YOUR ANSWER