# FILE NAME: vectors.R # R is efficient in computing with vector variables # By default, a variable holding a single number is a vector of length 1 # Below is an annotated summary of common operations with vector variables # Huseyin Kocak, May 24, 2016. University of Miami #R function c() combines (concatanes) values into a vector x = c(1.5, -3.2, 0.45, 4.1, 10) print(x) #Entry of a vector can be addressed by its index, its position in the vector #Unlike other programming languages, index of a vector in R starts from 1 print(x[1]) #to print the first entry of x print(x[4]) #to print the 4th entry of x x[4] = 7.6 #to change the value of the 4th entry of x to 7.6 print(x) #Can add an entry to a vector x[6] = 91 print(x) #An entry of a vector can be deleted using -index x = x[-6] print (x) #R function length() returns the number of entries of a vector #There are numerous function for vectors; try, for example #sort(), rev(), min(), mean(), sum(), prod() length_of_x = length(x) print(length_of_x) #Arithmetic of vectors is done entry-wise #+ addition, - subtraction, * product, / division, %*% crossproduct vector_1 = c(1.1, 2.3, 4.5) vector_2 = c(-1, 1.2, 0.5) vector_sum = vector_1 + vector_2 print(vector_sum) #Vector entries can be strings or booleans nucleotides = c("A", "C", "G", "T") print(nucleotides) #Vectors with patterns are useful. We will see a better way to generate them x = c(0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) print (x) squareRoot_x = sqrt(x) print(squareRoot_x)