Question

Write a program that generates a sequence of 20 random values between 0 and 99 in a list, prints the sequence, sorts it, and prints the sorted sequence. Use the list sort method.

Short answer

Generate 20 random numbers, print them, use the 'sort' method, and print the sorted list.

Step-by-step solution

Importing Required Module

To generate random numbers, we'll first import the 'random' module, which contains the 'randint' function we need to generate random integers.

Generating Random Values

Create a list of 20 random integers ranging from 0 to 99 using a list comprehension. This can be done using `[random.randint(0, 99) for _ in range(20)]`.

Printing the Unsorted Sequence

Use the 'print' function to display the unsorted list of random values to the console.

Sorting the List

Utilize the 'sort' method of list to sort the elements in ascending order. This is done with the syntax `random_values.sort()`, which sorts the list in-place.

Printing the Sorted Sequence

Finally, print the sorted list to show the difference before and after the sort operation.

Key concepts

Random Number Generation

In Python programming, generating random numbers is commonly required for tasks like simulation, sampling, and game development. To generate random numbers in Python, we rely on the `random` module, which offers a variety of functions. A popular method is `randint(a, b)`, which returns a random integer between the two specified numbers, inclusive.
For example, to generate a list of 20 random numbers between 0 and 99, you would use a list comprehension like:

• `[random.randint(0, 99) for _ in range(20)]`

This piece of code generates 20 random numbers because of the `range(20)` function, which creates an iteration of 20 steps. Each step calls `random.randint(0, 99)` to get a random integer. The underscore `_` is used here as a placeholder variable because the actual loop variable is not needed. The result is a list filled with random numbers.

List Sorting

Sorting is a fundamental operation often needed to process data efficiently. In Python, lists can be sorted using the built-in `sort()` method. This method organizes the list in ascending order by default, modifying the list in place for efficiency.
To sort a list, you can apply:

• `random_values.sort()`

Here, `random_values` refers to the list we want to sort. After calling `sort()`, the elements in the list will be rearranged in increasing order. This in-place sorting is advantageous as it minimizes memory usage by not requiring a separate sorted list.

Python List Methods

Python lists come with several useful built-in methods that make manipulating data straightforward. Understanding these methods can enhance your ability to work with lists effectively.
Key list methods include:

• `append(x)`: Adds an element `x` to the end of the list.
• `remove(x)`: Removes the first occurrence of the element `x` from the list.
• `insert(i, x)`: Inserts element `x` at index `i`.
• `sort()`: Sorts the list in ascending order.
• `reverse()`: Reverses the elements of the list in place.

These methods are vital for tasks such as adding new items, removing undesired elements, or preparing data for analysis.

Importing Modules

In Python, a module is a file containing Python definitions and statements, intended to define functions, classes, and variables. Importing modules allows you to reuse code written by others. This can significantly streamline your coding process.
To import a module, use:

• `import module_name`

For instance, to access random number operations, we import the `random` module with:

• `import random`

After this, functions within the module, like `random.randint()`, become accessible. Modules are essential as they extend Python's capabilities and offer solutions for various tasks, reducing the need to write code from scratch.