Vectors Exercises

These exercises cover the vectors sections of Introduction to R.

Exercise 1

• Create a vector containing the values 1,2,3,4,5
• Create a vector containing the values 1 to 100
• Create a vector containing the values 0,5,10,15,20
• Create a vector containing the values 1,1,2,2,3,3
• Create a vector containing the values 1,1,5,7,9,10

Exercise 2

• Create a vector containing the values 1 to 10.
• Create a new vector with all but the first and last value.
• Create a new vector with all but the second and fifth value.
• Create a new vector of square root of the sixth and seventh position.
• Create a new vector of alternating positions in the vector 1 to 10 using another vector.

Exercise 3

• Find the number of files in the present working directory.
• List the first file in the present working directory.

Exercise 4

• Create a vector of the gene names Gene_1, Gene_2, Gene_3, Gene_4
• Create a vector of the expression values 1000, 3000, 10000, 12000
• Create a vector of the gene lengths 100, 3000, 200, 1000
• Find the longest gene using logical expression.
• Identify genes which have a length greater than 100 and expression greater than 10000

Bonus questions

• Calculate the expression over the gene length for all genes (Length normalised expression - LNE).
• Identify genes with a length normalised expression greater than the average.