Question

Odd Numbers: Use the third argument of the range() function to make a list of the odd numbers from 1 to 20. Use a for loop to print each number.

Short answer

Use range(1, 21, 2) and a for loop to print odd numbers from 1 to 19.

Step-by-step solution

Understanding the Problem

We need to create a list of odd numbers from 1 to 20 and print them using a for loop.

Using range() Function

The range() function generates a sequence of numbers. Its syntax is range(start, stop, step). We need to start at 1, stop at 21 (since the stop is exclusive), and step by 2 to get all odd numbers.

Creating the List

Using range(1, 21, 2), we create the list of odd numbers. This will include 1, 3, 5, ..., 19.

Implementing the For Loop

Using a for loop, we iterate through each number in the list created using range().

Printing Each Number

Inside the for loop, we print each number, which will display odd numbers from 1 to 19.

Key concepts

For Loop

A for loop in Python is a control flow statement that helps you loop through a sequence, like lists, strings, dictionaries, or ranges. It allows you to execute a block of code repeatedly, once for each item in the sequence. This iterative process is extremely useful for working through items one by one.

The basic syntax of a for loop is: ```python for item in sequence: # code block to execute ``` The loop will continue executing for each element in the sequence until it reaches the last item.
For our exercise, the for loop iterates over numbers generated by the range function and prints each, neatly going through odd numbers in the specified range.

Understanding how to effectively use for loops can greatly enhance your programming skills, allowing for efficient management of repetitive tasks.

Range Function

The `range()` function in Python is an incredibly versatile function often used to generate a sequence of numbers. It's especially valuable when combined with loops, allowing us significantly to streamline repetitive tasks.

The `range()` function can take up to three arguments: `range(start, stop, step)`, where:

• `start` is the first number in the sequence; it's optional, and its default value is 0.
• `stop` is the number that signifies the end of the sequence but is not inclusive.
• `step` is the difference between each number in the sequence, which is also optional and defaults to 1.

In our specific task, we use `range(1, 21, 2)`. This tells Python to start at 1, end before 21, and step by 2. That way, we effectively generate a list of odd numbers up to 19.

Odd Numbers

Odd numbers are integers not divisible by 2. Examples include 1, 3, 5, and so on. Whenever you divide an odd number by 2, you'll always have a remainder of 1.

In this exercise, we're focusing on the odd numbers between 1 and 19. By using a step of 2 in the range function, we skip every other number and consequently only pick the odd ones.

Odd numbers are important because they are one of the simplest categories of numbers that possess distinct properties, which are often utilized in various algorithms and proofs in mathematics and computer science.

List Creation

In Python, lists are an essential data structure, allowing you to store multiple items in a single variable. Lists are ordered, changeable, and allow duplicate values, making them perfect for keeping a sequence of numbers like we've generated in this exercise.

To create a list of odd numbers using the `range()` function, we essentially convert the result of `range()` to a list like so: ```python list_of_odds = list(range(1, 21, 2)) ``` This constructs a new list holding all elements generated by the range—all odd numbers from 1 through 19.

Lists are highly useful in Python because they allow for flexible data manipulation. They support multiple operations like adding, removing, or accessing elements, which makes them quite powerful in both simple scripts and large applications.