Python For Loop – GATE 2020 PYQ with Solution

Python For Loop is one of the most important topics for GATE CSE 2026

In this post, we will cover for loop syntax, working, time complexity, and 3 GATE Previous Year Questions with detailed solutions.

What is For Loop in Python?

For loop in Python is used to iterate over a sequence like list, tuple, or range.

Syntax:

for variable in sequence:
    # code block

Example:

for i in range(3):
    print(i)

Output:

0
1
2

Why range(3) gives 0,1,2? Because range(n) starts from 0 and goes till n-1.

Time Complexity of For Loop

If loop runs n times, complexity is O(n). If nested for loop runs, complexity becomes O(n^2). This is frequently asked in GATE.

GATE Previous Year Questions on For Loop

Q1. GATE CSE 2020:

What will be output?

for i in range(0, 5, 2):
    print(i)

Solution: range(0,5,2) means start 0, stop 5, step 2. Output is 0, 2, 4.

Q2. GATE CSE 2019:

How many times will loop execute?

for i in range(10):
    for j in range(i):
        print(i,j)

Solution: Outer loop 10 times. Inner loop i times. Total complexity O(n^2). Total iterations = 45.

Q3. Common Interview Question:

What is difference between for and while loop?
Ans: For loop is used when number of iterations is known. While loop is used when condition-based iteration is needed.

Conclusion

For loop is easy but GATE always asks tricky questions on range() function and nested loops. Practice 10 questions daily from GateStudy.in

Next Post: Python While Loop GATE Questions.

Python For Loop – GATE 2020 PYQ with Solution | GateStudy.in