Doormat

Doormat

The code provided prints a doormat shape:

def doormat(height, width):

This line defines a function called doormat(), which takes two arguments: height and width.

height is the height of the doormat, and width is the width of the doormat.

result_list = []

The function works by first creating a list called result_list.

This list will contain the strings that will be printed to form the doormat.

for i in range(height // 2):

Next, the function iterates over the range 0 to height // 2.

This range will generate the numbers 0, 1, 2, ..., (height // 2) - 1.

result_list.append(('.|.' * (2 * i + 1)).center(width, '-'))

For each iteration, the function creates a string that consists of 2 * i + 1 repetitions of the pattern .|.’.

This string is then centered in a field of width characters, using the -character as the padding.

The centered string is then appended to the result_list list.

For example, if i is 0, the function will create the following string:

('.|.' * (2 * 0 + 1)).center(width, '-')

This will evaluate to the following string:

.|.

The center() method will then center this string in a field of width characters, using the - character as the padding.

For example, if width is 21, the center() method will evaluate to the following string:

---------.|.---------

This string is then appended to the result_list list.

The function repeats this process for all values of i from 0 to height // 2 - 1.

return print('\n'.join(result_list + ['WELCOME'.center(width, '-')] + result_list[::-1]))

Once the result_list list has been populated, the function returns a print statement that prints the strings in the list, separated by newline characters.

The list is also reversed before being printed, so that the bottom half of the doormat is a mirror image of the top half.

doormat(7, 21)

This line calls the doormat(7, 21) function with a height of 7 and width of 21.

Please note that:

The \n character represents a newline character.

The join() method takes a list of strings and joins them together, separated by the specified character.

The [::-1] syntax reverses the result_list list.

The // operator is the integer division operator. It returns the quotient of two integers, rounded down to the nearest integer. For example, 7 // 2 = 3.

The center() method takes two arguments: the string to be centered and the total width of the field in which the string will be centered.

The - character is used as the padding character. This means that if the string is shorter than the field width, the - character will be used to pad the string on the left and right sides until the desired field width is reached.

Here is an example of the output of the code:

---------.|.---------
------.|..|..|.------
---.|..|..|..|..|.---
-------WELCOME-------
---.|..|..|..|..|.---
------.|..|..|.------
---------.|.---------

Summary:

1 — The function first creates a list called result_list. Then, it iterates over the range height // 2 (excluding the middle element), and for each element, it appends the string ‘.|.’ * (2 * i + 1).

This string represents a row of the doormat pattern, with 2 * i + 1 dots and hyphens.

2 — After the loop, the function appends the string ‘WELCOME’.center(width, ‘-’) to result_list. This string represents the WELCOME message in the center of the doormat.

3 — Finally, the function reverses result_list and joins it with newline characters.

This creates a string containing the doormat pattern, with the WELCOME message in the center, and the top and bottom halves mirrored.

The function then prints the doormat pattern to the console.

Here is the source code on GitHub :

Doormat