Chained Comparison in Python

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When writing conditions in Python, you often need to compare multiple values. Instead of using multiple logical operators, Python offers a cleaner and more intuitive way to perform comparisons — chained comparisons.

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What is Chained Comparison?

Chained comparison allows you to combine multiple comparison operations in a single, readable expression, much like mathematical notation. For example:

x = 10
print(5 < x < 20)  # True

This statement is equivalent to:

(5 < x) and (x < 20)

Python evaluates 5 < x < 20 as a sequence of two conditions (5 < x and x < 20) joined by an and operator, making the code more concise and readable.

Benefits of Chained Comparison

• Improves readability — Expressions look more natural and resemble mathematical notation.
• Reduces redundancy — No need to repeat variables in multiple conditions.
• Enhances performance — Python evaluates expressions from left to right and stops early if a condition fails.

Examples of Chained Comparisons

1. Basic Numerical Comparison

a = 5
b = 10
c = 15
print(a < b < c)  # True (5 < 10 and 10 < 15)

2. Using Equality and Inequality

x = 10
print(5 < x <= 10)  # True (5 < 10 and 10 <= 10)

3. Mixing Operators

num = 7
print(1 < num != 5 < 10)  # True (1 < 7 and 7 != 5 and 5 < 10)

4. Function-Based Comparison

def get_age():
    return 25

print(18 <= get_age() < 30)  # True (age is between 18 and 30)

5. Comparison with Variables

x, y, z = 3, 5, 7
print(x < y > z)  # False (3 < 5 but 5 is not > 7)

When to Use Chained Comparisons

Chained comparisons are particularly useful in:

• Checking if a value lies within a range.
• Verifying multiple conditions in a single line.
• Writing more readable and concise conditional statements.

Conclusion

Chained comparison in Python is a powerful feature that simplifies conditional checks and enhances code readability. By adopting this technique, you can write more elegant and efficient Python programs. So next time you find yourself writing multiple logical conditions, try using chained comparisons for cleaner code!