Output of Python Program | Set 3 (Loops)

Output of Python Program | Set 3 (Loops)

Loops are fundamental in Python programming, allowing you to execute a block of code multiple times. In this blog, we will analyze different Python programs involving loops and understand their output. This will strengthen your grasp on how for and while loops operate in Python.

For Loop Example

Consider the following for loop that prints numbers from 0 to 4:

for i in range(5):
    print(i)

Output:

0
1
2
3
4

Here, the range(5) function generates numbers from 0 up to, but not including, 5. The loop prints each number in the sequence.

While Loop Example

Next, a simple while loop that counts down from 5 to 1:

count = 5
while count > 0:
    print(count)
    count -= 1

Output:

5
4
3
2
1

The loop continues as long as the condition count > 0 is true, decrementing the counter each iteration.

Nested Loops

Loops can also be nested to perform more complex iterations. Here's an example:

for i in range(1, 4):
    for j in range(1, 3):
        print(f"i = {i}, j = {j}")

Output:

i = 1, j = 1
i = 1, j = 2
i = 2, j = 1
i = 2, j = 2
i = 3, j = 1
i = 3, j = 2

Here, for each value of i, the inner loop runs through all values of j.

Practice Problem

Try to predict the output of the following Python program:

total = 0
for num in range(1, 6):
    if num % 2 == 0:
        total += num
print(total)

Explanation: The program iterates through numbers 1 to 5, adds the even numbers to total, and then prints the result.

Solution to Practice Problem

The even numbers between 1 and 5 are 2 and 4. So, the sum is:

2 + 4 = 6

Output:

6

Conclusion

Loops are a core concept in Python that enable repetitive tasks to be performed efficiently. Understanding their flow and output is essential for writing effective code. Practice various loop constructs to master their behavior and output prediction.