DEV Community

Lakshmi Pritha Nadesan
Lakshmi Pritha Nadesan

Posted on

Day 16 - Slicing,for loop and nested loop

Slicing:

Slicing is a programming technique used in Python to extract a portion of a sequence. By specifying a range of indices, you can retrieve specific parts of the sequence without altering the original data.

Example:

name=[2,8]

Step operator:

A step operator refers to the ability to specify an increment for iteration in loops. In Python, this is often used with the range() function, which allows specifying a step to control how the loop variable changes after each iteration.

Example:

name[2:8:3]
3 is a step operator.

Program using two variable:

start,end= 1,6
while end>1:
    for num in range(start,end):
        print(num, end=" ")
    print()
    end-=1   
Enter fullscreen mode Exit fullscreen mode

Same program using one variable:

end= 6
while end>1:
    for num in range(1,end):
        print(num, end=" ")
    print()
    end-=1  
Enter fullscreen mode Exit fullscreen mode

*Same program without using variable or using nested loop:
*

for end in range(6,1,-1):
    for num in range(1,end):
        print(num, end=" ")
    print()  
Enter fullscreen mode Exit fullscreen mode

Output:

1 2 3 4 5 
1 2 3 4 
1 2 3 
1 2 
1 

Enter fullscreen mode Exit fullscreen mode

Nested loop:

A nested for loop is a loop inside another loop.

Syntax:

for outer in outer_iterable:
    for inner in inner_iterable:
Enter fullscreen mode Exit fullscreen mode

1.The outer loop runs first.
2.For every iteration of the outer loop, the inner loop runs completely.
3.When the inner loop finishes, the outer loop proceeds to its next iteration.

for row in range(2,7):
    for col in range(1,row):
        print(col, end=' ')
    print()
Enter fullscreen mode Exit fullscreen mode
1 
1 2 
1 2 3 
1 2 3 4 
1 2 3 4 5 
Enter fullscreen mode Exit fullscreen mode
for row in range(5):
    for col in range(5-row):
        print(col+1, end=' ')
    print()
Enter fullscreen mode Exit fullscreen mode
1 2 3 4 5 
1 2 3 4 
1 2 3 
1 2 
1 
Enter fullscreen mode Exit fullscreen mode
for row in range(5):
    for col in range(5-row):
        print((col+1)*2, end=' ')
    print()
Enter fullscreen mode Exit fullscreen mode
2 4 6 8 10 
2 4 6 8 
2 4 6 
2 4 
2 
Enter fullscreen mode Exit fullscreen mode
for row in range(5):
    for col in range(5-row):
        print((col+1)*(row+1), end=' ')
    print()
Enter fullscreen mode Exit fullscreen mode
1 2 3 4 5 
2 4 6 8 
3 6 9 
4 8 
5 
Enter fullscreen mode Exit fullscreen mode

Task:

(https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3v84djylxrixjnllx8hq.jpg)

for row in range(5):
    for col in range(5-row):
        print((col+1)*3, end=" ")
    print()

Enter fullscreen mode Exit fullscreen mode
3 6 9 12 15 
3 6 9 12 
3 6 9 
3 6 
3 
Enter fullscreen mode Exit fullscreen mode
for row in range(5):
    for col in range(row+1):
        print(5-col, end=' ')
    print()
Enter fullscreen mode Exit fullscreen mode
5 
5 4 
5 4 3 
5 4 3 2 
5 4 3 2 1 
Enter fullscreen mode Exit fullscreen mode

Top comments (0)