Numeric and character vectors in R Programming - Mini Project: Build & Apply

Numeric and character vectors

📖 Scenario: You are organizing a small party and want to keep track of the number of guests and their favorite drinks.

🎯 Goal: Create numeric and character vectors in R to store the number of guests and their favorite drinks, then display the information.

📋 What You'll Learn

Create a numeric vector called guest_counts with the exact values 5, 3, 7

Create a character vector called favorite_drinks with the exact values "Tea", "Coffee", "Juice"

Create a variable called total_guests that sums all values in guest_counts

Print the total_guests value

Print the favorite_drinks vector

💡 Why This Matters

🌍 Real World

Keeping track of guest counts and preferences helps in planning events and ordering the right amount of food and drinks.

💼 Career

Data analysts and event planners often work with numeric and character data to summarize and report information clearly.

1

Create the numeric vector

Create a numeric vector called guest_counts with the exact values 5, 3, 7.

R Programming

# Create the numeric vector guest_counts with values 5, 3, 7
# Your code here

Hint

Use the c() function to combine numbers into a vector.

2

Create the character vector

Create a character vector called favorite_drinks with the exact values "Tea", "Coffee", "Juice".

R Programming

guest_counts <- c(5, 3, 7)
# Create the character vector favorite_drinks with values "Tea", "Coffee", "Juice"
# Your code here

Hint

Use the c() function with quotes around each drink name.

3

Calculate total guests

Create a variable called total_guests that sums all values in the guest_counts vector.

R Programming

guest_counts <- c(5, 3, 7)
favorite_drinks <- c("Tea", "Coffee", "Juice")
# Create total_guests by summing guest_counts
# Your code here

Hint

Use the sum() function to add all numbers in the vector.

4

Print the results

Print the value of total_guests and then print the favorite_drinks vector.

R Programming

guest_counts <- c(5, 3, 7)
favorite_drinks <- c("Tea", "Coffee", "Juice")
total_guests <- sum(guest_counts)
# Print total_guests
# Print favorite_drinks
# Your code here

Hint

Use print() to show the values on the screen.

Practice

1. Which of the following correctly creates a numeric vector in R?

easy

A. c(TRUE, FALSE, TRUE)

B. c("one", "two", "three")

C. c(1, "two", 3)

D. c(1, 2, 3, 4)

Solution

1. Step 1: Understand numeric vector creation

   Numeric vectors contain only numbers, so elements must be numeric values.

2. Step 2: Check each option's elements

   c(1, 2, 3, 4) has only numbers, so it is a numeric vector. c("one", "two", "three") has text, c(TRUE, FALSE, TRUE) has logical values, and c(1, "two", 3) mixes numbers and text, which converts all to characters.

3. Final Answer:

   c(1, 2, 3, 4) -> Option D

4. Quick Check:

   Numeric vector = c(1, 2, 3, 4) [OK]

Hint: Numeric vectors contain only numbers inside c() [OK]

Common Mistakes:

• Mixing numbers and text creates character vector
• Confusing logical vectors with numeric
• Using quotes around numbers

2. Which of these is the correct syntax to create a character vector in R?

easy

A. c(1, 2, 3)

B. c("apple", "banana", "cherry")

C. c(TRUE, FALSE, TRUE)

D. c(1, "banana", 3)

Solution

1. Step 1: Identify character vector syntax

   Character vectors contain text strings, which must be inside quotes.

2. Step 2: Check options for quoted text

   c("apple", "banana", "cherry") has all elements as quoted text strings, so it is a character vector. c(1, 2, 3) is numeric, c(TRUE, FALSE, TRUE) is logical, and c(1, "banana", 3) mixes types causing coercion.

3. Final Answer:

   c("apple", "banana", "cherry") -> Option B

4. Quick Check:

   Character vector = c("apple", "banana", "cherry") [OK]

Hint: Use quotes around text to create character vectors [OK]

Common Mistakes:

• Forgetting quotes around text
• Mixing types in one vector
• Using numbers without quotes for text

3. What is the output of this R code?

x <- c(5, 10, 15)
y <- c("a", "b", "c")
z <- c(x, y)
print(z)

medium

A. [1] "5" "10" "15" "a" "b" "c"

B. [1] 5 10 15 "a" "b" "c"

C. [1] 5 10 15 NA NA NA

D. Error: cannot combine numeric and character vectors

Solution

1. Step 1: Understand vector combining rules in R

   When combining numeric and character vectors, R converts all elements to character to keep the same type.

2. Step 2: Analyze the combined vector z

   Vector z contains numbers 5, 10, 15 and characters "a", "b", "c". All numbers become strings, so print shows all as character strings.

3. Final Answer:

   [1] "5" "10" "15" "a" "b" "c" -> Option A

4. Quick Check:

   Mixed vector coerces to character = [1] "5" "10" "15" "a" "b" "c" [OK]

Hint: Mixed types in vector become character strings [OK]

Common Mistakes:

• Expecting numeric values to stay numeric
• Thinking R throws error on combining types
• Assuming NA values appear for mismatched types

4. Identify the error in this R code:

vec <- c(1, 2, "three", 4)
sum(vec)

medium

A. No error; sum returns 10

B. sum() returns NA due to mixed types

C. Error because sum() cannot handle character vectors

D. Error because c() cannot mix numbers and text

Solution

1. Step 1: Understand vector creation with mixed types

   c(1, 2, "three", 4) creates a character vector because of the text element "three".

2. Step 2: Check sum() behavior on character vectors

   sum() expects numeric input. Passing a character vector causes an error because it cannot sum text.

3. Final Answer:

   Error because sum() cannot handle character vectors -> Option C

4. Quick Check:

   sum(character vector) = Error [OK]

Hint: sum() needs numeric vectors, not characters [OK]

Common Mistakes:

• Assuming sum() converts characters to numbers
• Thinking c() forbids mixing types (it coerces instead)
• Expecting sum() to return NA silently

5. You have two vectors:

nums <- c(2, 4, 6, 8)
chars <- c("2", "4", "6", "8")

How can you create a numeric vector from chars and add it to nums element-wise?

hard

A. nums + as.numeric(chars)

B. nums + chars

C. as.character(nums) + chars

D. sum(nums, chars)

Solution

1. Step 1: Convert character vector to numeric

   Use as.numeric(chars) to change text numbers to numeric values.

2. Step 2: Add numeric vectors element-wise

   Adding nums + as.numeric(chars) adds corresponding elements correctly.

3. Final Answer:

   nums + as.numeric(chars) -> Option A

4. Quick Check:

   Convert chars to numeric before adding = nums + as.numeric(chars) [OK]

Hint: Convert text to numbers with as.numeric() before math [OK]

Common Mistakes:

• Adding numeric and character vectors directly
• Using sum() instead of element-wise addition
• Converting numeric to character instead of chars to numeric