Comparison operators in Python - Step-by-Step Execution

Concept Flow - Comparison operators

Start with two values

↓

Apply comparison operator

↓

Evaluate condition: True or False?

↓

Use result in program

↓

End

Comparison operators check how two values relate and give True or False as result.

Execution Sample

Python

a = 5
b = 3
result = a > b
print(result)

This code compares if 5 is greater than 3 and prints the result.

Execution Table

Step	Expression	Evaluation	Result
1	a = 5	Assign 5 to a	a = 5
2	b = 3	Assign 3 to b	b = 3
3	result = a > b	Is 5 greater than 3?	True
4	print(result)	Print the value of result	True

💡 Program ends after printing the comparison result True

Variable Tracker

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

Key Moments - 3 Insights

Why does 'a > b' give True instead of a number?

Comparison operators return True or False, not numbers. See execution_table step 3 where 'result = a > b' evaluates to True.

What happens if a and b are equal with 'a > b'?

If a equals b, 'a > b' is False because 5 is not greater than 5. The condition must be strictly greater.

Can comparison operators be used with other types like strings?

Yes, but they compare based on alphabetical order or other rules. For example, 'apple' < 'banana' is True.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of 'result' after step 3?

A False

B True

C 5

D 3

💡 Hint

Check the 'Result' column in execution_table row with Step 3.

At which step is the variable 'b' assigned a value?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at the 'Expression' column in execution_table to find when 'b = 3' happens.

If we change 'a = 5' to 'a = 2', what will 'result' be at step 3?

A False

B True

C 5

D 2

💡 Hint

Compare new 'a' value with 'b' in the condition 'a > b' at step 3.

Concept Snapshot

Comparison operators compare two values and return True or False.
Common operators: >, <, >=, <=, ==, !=
Used to check conditions in programs.
Example: 5 > 3 is True.
They do not return numbers, only boolean results.

Full Transcript

This visual trace shows how comparison operators work in Python. We start by assigning values to variables a and b. Then we compare a > b, which checks if a is greater than b. The result is True or False, not a number. Finally, we print the result. The variable tracker shows how a, b, and result change step by step. Key moments clarify common confusions like why the comparison returns True/False and how equality affects the result. The quiz tests understanding by asking about variable values and outcomes at specific steps.

Practice

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

easy

A. ==

B. =

C. !=

D. >

Solution

1. Step 1: Understand the equality operator

   The operator == is used to check if two values are equal in Python.

2. Step 2: Differentiate from assignment and other operators

   = is for assignment, != means not equal, and > means greater than.

3. Final Answer:

   == -> Option A

4. Quick Check:

   Equality check = == [OK]

Hint: Remember: double equals means equality check [OK]

Common Mistakes:

• Confusing = with ==
• Using != for equality
• Using > instead of ==

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

easy

A. x != 10

B. x <> 10

C. x =! 10

D. x !== 10

Solution

1. Step 1: Identify the correct not equal operator

   In Python, != is the correct operator for 'not equal'.

2. Step 2: Recognize invalid syntax

   <> is not valid in Python, =! and !== are syntax errors.

3. Final Answer:

   x != 10 -> Option A

4. Quick Check:

   Not equal operator = != [OK]

Hint: Use != for not equal, not <> or !== [OK]

Common Mistakes:

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

3. What will be the output of this code?

print(5 > 3 and 2 == 2)

medium

A. SyntaxError

B. False

C. True

D. None

Solution

1. Step 1: Evaluate each comparison

   5 > 3 is True, and 2 == 2 is True.

2. Step 2: Apply the 'and' operator

   True and True results in True.

3. Final Answer:

   True -> Option C

4. Quick Check:

   Both conditions True, so output True [OK]

Hint: Both sides must be True for 'and' to be True [OK]

Common Mistakes:

• Confusing 'and' with 'or'
• Misreading comparison results
• Expecting syntax error

4. Find the error in this code snippet:

if 4 =< 5:
    print("Yes")

medium

A. Missing colon after if statement

B. The operator =< is invalid in Python

C. Indentation error in print statement

D. Variable 4 cannot be compared

Solution

1. Step 1: Check the comparison operator

   The operator =< is not valid in Python; the correct operator is <=.

2. Step 2: Verify other syntax parts

   The colon is present and indentation is correct; 4 is a valid integer literal for comparison.

3. Final Answer:

   The operator =< is invalid in Python -> Option B

4. Quick Check:

   Use <= for less than or equal [OK]

Hint: Remember: less or equal is <=, not =< [OK]

Common Mistakes:

• Swapping operator symbols
• Missing colon
• Incorrect indentation

5. You want to check if a number n is between 10 and 20 inclusive. Which expression correctly uses comparison operators in Python?

hard

A. n > 10 or n < 20

B. 10 < n < 20

C. n >= 10 and n < 20

D. 10 <= n <= 20

Solution

1. Step 1: Understand inclusive range check

   Inclusive means n can be equal to 10 or 20, so use <= operators.

2. Step 2: Evaluate each option

   10 <= n <= 20 uses chained comparison which is correct and concise. 10 < n < 20 excludes 10 and 20. n >= 10 and n < 20 excludes 20. n > 10 or n < 20 uses 'or' which is incorrect for range check.

3. Final Answer:

   10 <= n <= 20 -> Option D

4. Quick Check:

   Use chained <= for inclusive range [OK]

Hint: Use chained comparisons for range checks [OK]

Common Mistakes:

• Using < instead of <=
• Using 'or' instead of 'and'
• Not including boundary values