Difference between method types in Python - Performance Comparison

Time Complexity: Difference between method types

O(n)

Understanding Time Complexity

We want to see how the time it takes to run code changes when using different method types in Python classes.

Which method type runs faster or slower as the input grows?

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

class Example:
    def instance_method(self, data):
        total = 0
        for item in data:
            total += item
        return total

    @classmethod
    def class_method(cls, data):
        total = 0
        for item in data:
            total += item
        return total

    @staticmethod
    def static_method(data):
        total = 0
        for item in data:
            total += item
        return total

This code shows three method types doing the same task: adding numbers in a list.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: Looping through each item in the list to add values.
• How many times: Once for each item in the input list.

How Execution Grows With Input

As the list gets bigger, the number of additions grows in the same way.

Input Size (n)	Approx. Operations
10	10 additions
100	100 additions
1000	1000 additions

Pattern observation: The work grows directly with the size of the input list.

Final Time Complexity

Time Complexity: O(n)

This means the time to run grows in a straight line with the number of items to add.

Common Mistake

[X] Wrong: "Static methods are always faster than instance or class methods because they don't use self or cls."

[OK] Correct: All three methods do the same loop work here, so their time depends on the input size, not on method type.

Interview Connect

Understanding how method types affect performance helps you explain your code choices clearly and shows you know how Python works under the hood.

Self-Check

"What if the methods did not loop over the data but called another function that loops? How would the time complexity change?"