Unlocking the Power of Vectors in R

What is a Vector in R?

Imagine you need to record the ages of five employees. Instead of creating five separate variables, you can store all the data in a single entity called a vector. A vector is the fundamental data structure in R that holds data of similar types.

Creating a Vector in R

To create a vector, you can use the c() function, which combines multiple elements into a single vector. For instance, let’s create a vector named employees with elements “Sabby”, “Cathy”, and “Lucy”.

employees <- c("Sabby", "Cathy", "Lucy")

Unpacking Vector Elements

Each element in a vector has a corresponding index number, starting from 1. You can access these elements using their index numbers. For example, if you have a vector languages with elements “Swift”, “Java”, and “R”, you can access the first element using languages[1], which returns “Swift”.

languages <- c("Swift", "Java", "R")
print(languages[1])  # Output: [1] "Swift"

Modifying Vector Elements

Need to make changes to a vector element? Simply reassign a new value to the specific index. For instance, you can change the second element of a vector from “Repeat” to “Sleep” by assigning a new value.

actions <- c("Run", "Repeat", "Jump")
actions[2] <- "Sleep"
print(actions)  # Output: [1] "Run"    "Sleep"  "Jump"

Working with Numeric Vectors

Creating a numeric vector is similar to creating a string vector. You can use the c() function or the more efficient : operator to create a sequence of numbers. For example, numbers <- 1:5 creates a vector with numerical values from 1 to 5.

numbers <- 1:5
print(numbers)  # Output: [1] 1 2 3 4 5

Repeating Vectors

The rep() function allows you to repeat elements of vectors. You can repeat the entire vector or each element individually. For instance, rep(numbers, times = 2) repeats the entire vector two times, while rep(numbers, each = 2) repeats each element two times.

numbers <- 1:5
print(rep(numbers, times = 2))  # Output: [1] 1 2 3 4 5 1 2 3 4 5
print(rep(numbers, each = 2))  # Output: [1] 1 1 2 2 3 3 4 4 5 5

Looping Through Vectors

Want to access all elements of a vector? Use a for loop to iterate through each element. This is particularly useful when working with large datasets.

numbers <- 1:5
for (num in numbers) {
  print(num)
}
# Output:
# [1] 1
# [1] 2
# [1] 3
# [1] 4
# [1] 5

Measuring Vector Length

Finally, you can use the length() function to find the number of elements present inside a vector. This is useful when working with dynamic datasets.

numbers <- 1:5
print(length(numbers))  # Output: [1] 5