Comparison operators in R Programming - Step-by-Step Execution

Concept Flow - Comparison operators

Start

↓

Evaluate Left Value

↓

Evaluate Right Value

↓

Apply Comparison Operator

↓

Result: TRUE or FALSE

↓

End

The program compares two values using a comparison operator and produces TRUE or FALSE as the result.

Execution Sample

R Programming

a <- 5
b <- 3
result <- a > b
print(result)

This code compares if a is greater than b and prints TRUE or FALSE.

Execution Table

Step	Action	Evaluation	Result
1	Assign a	a <- 5	a = 5
2	Assign b	b <- 3	b = 3
3	Compare a > b	5 > 3	TRUE
4	Assign result	result <- TRUE	result = TRUE
5	Print result	print(result)	[1] TRUE

💡 All steps completed, comparison result printed.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
a	undefined	5	5	5	5	5
b	undefined	undefined	3	3	3	3
result	undefined	undefined	undefined	undefined	TRUE	TRUE

Key Moments - 2 Insights

Why does the comparison a > b return TRUE?

Because at step 3 in the execution_table, the values 5 and 3 are compared, and 5 is indeed greater than 3, so the result is TRUE.

What type of value does a comparison operator return in R?

As shown in step 3 and 5, comparison operators return a logical value: TRUE or FALSE.

Visual Quiz - 3 Questions

Look at the execution_table at step 3, what is the result of the comparison a > b?

A 5

B FALSE

C TRUE

D 3

💡 Hint

Check the 'Result' column in step 3 of the execution_table.

At which step is the variable 'result' assigned the comparison outcome?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Action' column for assignment of 'result' in the execution_table.

If we change b to 7, what would be the result of a > b at step 3?

A FALSE

B TRUE

C 5

D 7

💡 Hint

Compare values 5 and 7 in the 'Evaluation' column of step 3.

Concept Snapshot

Comparison operators in R compare two values and return TRUE or FALSE.
Common operators: >, <, >=, <=, ==, !=
Syntax example: result <- a > b
Result is logical (TRUE/FALSE).
Used for decision making and filtering.

Full Transcript

This visual execution trace shows how comparison operators work in R. First, variables a and b are assigned values 5 and 3. Then, the comparison a > b is evaluated as 5 > 3, which is TRUE. This result is stored in the variable 'result' and printed. Comparison operators always return TRUE or FALSE, which are logical values in R. This helps programs decide what to do next based on conditions.

Practice

1. Which of the following comparison operators in R checks if two values are equal?

easy

A. !=

B. =

C. <>

D. ==

Solution

1. Step 1: Understand equality operator in R

   In R, the operator to check if two values are equal is ==.

2. Step 2: Differentiate from other operators

   = is for assignment, != means not equal, and <> is not valid in R.

3. Final Answer:

   == -> Option D

4. Quick Check:

   Equality operator = == [OK]

Hint: Use double equals (==) to test equality in R [OK]

Common Mistakes:

• Using single = instead of ==
• Confusing != with equality
• Using <> which is invalid in R

2. Which of the following is the correct syntax to check if variable x is NOT equal to 10 in R?

easy

A. x != 10

B. x <> 10

C. x =! 10

D. x !== 10

Solution

1. Step 1: Identify the not equal operator in R

   R uses != to check if two values are not equal.

2. Step 2: Check syntax correctness

   <> and !== are not valid in R, and =! is incorrect syntax.

3. Final Answer:

   x != 10 -> Option A

4. Quick Check:

   Not equal operator = != [OK]

Hint: Use != to check inequality in R [OK]

Common Mistakes:

• Using <> which is invalid in R
• Writing =! instead of !=
• Using !== which is from other languages

3. What is the output of the following R code?

x <- 5
y <- 7
x > y

medium

A. FALSE

B. TRUE

C. 5

D. Error

Solution

1. Step 1: Compare values of x and y

   x is 5 and y is 7, so 5 > 7 is being checked.

2. Step 2: Evaluate the comparison

   Since 5 is not greater than 7, the expression returns FALSE.

3. Final Answer:

   FALSE -> Option A

4. Quick Check:

   5 > 7 = FALSE [OK]

Hint: Compare numbers directly; 5 > 7 is false [OK]

Common Mistakes:

• Confusing > with <
• Expecting numeric output instead of logical
• Thinking it causes an error

4. Identify the error in this R code snippet:

if (x = 10) { print("Yes") }

medium

A. No error, code is correct

B. Missing curly braces

C. Using = instead of ==

D. print() is incorrect function

Solution

1. Step 1: Check the condition syntax in if statement

   In R, to compare values, use ==, not =.

2. Step 2: Understand the difference between assignment and comparison

   = assigns a value, but == tests equality. Using = in if condition causes an error or unexpected behavior.

3. Final Answer:

   Using = instead of == -> Option C

4. Quick Check:

   Comparison needs ==, not = [OK]

Hint: Use == for comparison inside if() [OK]

Common Mistakes:

• Using = instead of ==
• Ignoring syntax errors from wrong operator
• Thinking = works for comparison

5. You want to filter a vector v <- c(3, 5, 7, 9) to keep only values greater than or equal to 5. Which R expression correctly uses comparison operators to do this?

hard

A. v[v => 5]

B. v[v >= 5]

C. v[v = 5]

D. v[v >== 5]

Solution

1. Step 1: Understand filtering with comparison

   To keep values >= 5, use the operator >= inside the indexing brackets.

2. Step 2: Check syntax correctness

   =>, =, and >== are invalid operators in R.

3. Final Answer:

   v[v >= 5] -> Option B

4. Quick Check:

   Use >= for greater or equal in filtering [OK]

Hint: Use >= for greater or equal comparisons [OK]

Common Mistakes:

• Using => which is invalid
• Using = instead of comparison operator
• Combining > and == incorrectly