Range and Nested Loops

Range Function (range())

The range() function is a built-in function in Python used to generate a sequence of numbers. It takes up to three arguments:

  • start (optional): The starting number of the sequence (inclusive). Defaults to 0.
  • stop (required): The number one greater than the last element in the sequence (exclusive).
  • step (optional): The increment between each number in the sequence. Defaults to 1.

Here's how it's used:

Python
# Generate numbers from 0 to 4 (excluding 4)
numbers = range(5)
print(list(numbers))  # Output: [0, 1, 2, 3]

# Generate numbers from 2 to 10 (excluding 10) with a step of 2
even_numbers = range(2, 10, 2)
print(list(even_numbers))  # Output: [2, 4, 6, 8]

Important Note: range() itself doesn't create a list, it creates a range object. To get a list of numbers from the range, you can convert it using list().

Nested Loops

Nested loops involve placing one loop inside another loop. The inner loop executes completely for each iteration of the outer loop. This allows you to iterate over elements in multi-dimensional data structures or perform operations on combinations of elements.

Example 1: Printing a Square Pattern

Python
for i in range(5):
    for j in range(5):
        print("*", end="")  # Print an asterisk without a newline
    print()  # Move to a new line after each inner loop completes

This code creates a nested loop. The outer loop (i) iterates 5 times. For each iteration of the outer loop, the inner loop (j) also iterates 5 times, printing an asterisk (*) each time. Since print() is called within the inner loop with end="", it prints 5 asterisks on the same line. The outer loop then moves to the next iteration, and the inner loop repeats, creating a 5x5 square of asterisks.

Example 2: Iterating Over a List of Lists

Python
data = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

for row in data:
    for element in row:
        print(element, end=" ")  # Print each element with a space
    print()  # Move to a new line after each row

This code iterates over a 2D list (data). The outer loop (row) iterates over each sub-list (row) in the data. The inner loop (element) iterates over the elements within each sub-list, printing each element with a space. Finally, a newline is printed after each row is processed.

Applications of Nested Loops:

  • Traversing multi-dimensional data structures (like matrices or grids).
  • Finding patterns or relationships between elements in data.
  • Performing calculations on combinations of elements.
  • Creating complex output formats (like tables or visualizations).
Search
Categories
Read More
Chemistry
UMTA UACE UMTA CHEMISTRY PAPER 1 2024 MOCKS
UMTA UACE CHEMISTRY PAPER 1 2024 MOCKS
By Landus Mumbere Expedito 2024-08-01 16:10:54 0 10K
Chemistry
UTEB MOCK CHEMISTRY PAPER 1 2024
UTEB MOCK CHEMISTRY PAPER 1 2024
By Landus Mumbere Expedito 2024-08-03 15:32:50 0 9K
Technology
Transaction Processing Systems (TPS)
These are information systems that manage and process data from business transactions. A...
By Business Information Systems (BIS) Course 2024-07-31 18:42:51 0 8K
Technology
Network topologies
Network topology refers to the arrangement of various elements (like nodes and links) in a...
By Mpatswe Francis 2024-10-03 22:58:40 0 8K
Technology
Popular Linux Distributions
Linux distributions, or distros, come in various forms tailored to different user needs, ranging...
By Tebtalks Access 2024-07-13 07:29:49 0 8K
Tebtalks https://tebtalks.com