Python Comparison Operators Explained: A Complete Guide with Examples

1. What Are Comparison Operators in Python?

The Role of Comparison Operators

Example: Basic Conditional Branching with Comparison Operators

a = 10
b = 20

if a < b:
    print("a is smaller than b")
else:
    print("a is greater than b")

Comparison Operators and Boolean Type

2. List of Major Comparison Operators in Python

Main Comparison Operators

Example: Basic Comparisons with Operators

x = 5
y = 10

print(x == y)  # False: x and y are not equal
print(x != y)  # True: x and y are not equal
print(x < y)   # True: x is smaller than y

3. Using Comparison Operators with Numbers

Basic Numeric Comparison

a = 7
b = 3

print(a > b)  # True: a is greater than b
print(a < b)  # False: a is not smaller than b

Comparing Floating-Point Numbers

a = 0.1 + 0.2
print(a == 0.3)  # False: due to floating-point error

epsilon = 1e-10
if abs(a - 0.3) < epsilon:
    print("Almost equal")

4. Using Comparison Operators with Strings and Lists

String Comparison

print("apple" > "banana")  # False: "a" is smaller than "b"
print("apple" == "apple")  # True: Strings are equal

List Comparison

list1 = [1, 2, 3]
list2 = [1, 2, 4]

print(list1 < list2)  # True: because 3 < 4

5. Chaining Multiple Comparison Operators

Example of Chained Comparisons

x = 15
if 10 < x < 20:
    print("x is greater than 10 and smaller than 20")

Checking for Equal Values

a = 10
b = 10
c = 10

if a == b == c:
    print("All values are equal")

6. Applying Comparison Operators in Conditional Statements

Conditional Branching with if-else

x = 10
if x > 5:
    print("x is greater than 5")
else:
    print("x is 5 or smaller")

Evaluating Multiple Conditions

age = 18
if age < 13:
    print("You are a child")
elif age < 20:
    print("You are a teenager")
else:
    print("You are an adult")

Complex Conditions with and and or

a = 20
if a > 10 and a < 30:
    print("a is greater than 10 and smaller than 30")

7. Important Notes and Best Practices for Python Operators

Difference Between == and is

Example: Difference Between == and is

a = [1, 2, 3]
b = [1, 2, 3]

print(a == b)  # True: Values are equal
print(a is b)  # False: Different objects

Notes on Floating-Point Comparisons

Example: Comparing Floating-Point Numbers with Tolerance

a = 0.1 + 0.2
epsilon = 1e-10

if abs(a - 0.3) < epsilon:
    print("a is very close to 0.3")

Notes on Chained Comparisons

Good Example: Using and to Combine Conditions

a = 50
b = [10, 20, 50, 100]

if 30 < a and a in b:
    print("a is greater than 30 and included in the list")

Comparing Mutable Objects like Lists and Dictionaries

Example: List Comparison

list1 = [1, 2, 3]
list2 = [1, 2, 3]

print(list1 == list2)  # True: Values are equal
print(list1 is list2)  # False: Different objects

Best Practices

1. Keep your code simple and readable Avoid overly complex chained comparisons. Instead, use and or or to separate conditions clearly.
2. Use is and == appropriately Use == when checking value equality, and is when confirming if two objects are identical.
3. Be careful with floating-point comparisons Avoid direct equality checks with floats. Use tolerance-based comparisons with abs to account for precision errors.

8. Conclusion: Mastering Comparison Operators in Python