Comparison operators in Python

Introduction

Comparison operators help us check if things are equal, bigger, or smaller. They tell us true or false.

Checking if a password matches the saved one.

Finding out if a number is bigger than another.

Seeing if two words are the same.

Deciding if someone is old enough to enter a game.

Comparing scores to find the winner.

Syntax

Python

value1 operator value2

Operators return True or False.

Common operators: ==, !=, >, <, >=, <=

Examples

Checks if 5 is equal to 5. Result is True.

Python

5 == 5

Checks if 3 is less than 7. Result is True.

Python

3 < 7

Checks if "apple" is not equal to "orange". Result is True.

Python

"apple" != "orange"

Checks if 10 is greater than or equal to 10. Result is True.

Python

10 >= 10

Sample Program

This program compares two numbers using different comparison operators and prints True or False.

Python

a = 10
b = 20
print(a == b)   # False because 10 is not 20
print(a != b)   # True because 10 is not 20
print(a < b)  # True because 10 is less than 20
print(a >= 10) # True because a is equal to 10

Important Notes

Use double equals (==) to check equality, not a single equals (=) which assigns values.

Comparison operators always return a boolean: True or False.

You can compare numbers, text, and other types that support comparison.

Summary

Comparison operators check how two values relate.

They return True or False.

Common operators: ==, !=, >, <, >=, <=

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