5 Best Ways to Program a Pattern of ‘g’ in Python

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πŸ’‘ Problem Formulation: In this article, we discuss how to create a program in Python that outputs the pattern of the lowercase letter ‘g’. This could be utilized, for example, in creating ASCII art or for educational purposes in learning Python loops and string manipulation. The input would generally specify the size of the pattern, and the desired output is a visually recognizable pattern of the character ‘g’ on the command line or console.

Method 1: Using Nested Loops

An approach to print the pattern ‘g’ is to use nested loops that iterate over rows and columns. This method involves checking if the current row and column index fall within the boundaries that would form the letter ‘g’. It requires a bit of logical structuring to define where ‘g’ exists in the grid of characters.

Here’s an example:

size = 5
for i in range(size):
    for j in range(size):
        if ((j == 1 and i != 0 and i != size - 1) or ((i == 0 or i == size - 1) and j > 1 and j  1) or (j == size - 1 and i > (size // 2) and i != size - 1) or (i > (size // 2) and j == 1 and i != size - 1)):
            print('*', end = ' ')
        else:
            print(' ', end = ' ')
    print()

Output:

  * * *   
*       *
*       *
*   * * *
*     *   
*     *

This method relies on a manual, logical distribution of the asterisk (*) characters to create the pattern of ‘g’. The for-loops combined with if-conditions effectively map out the shape of ‘g’ on a grid as specified by the size variable. While the approach is straightforward, it involves a detailed setup of conditions to get the pattern right.

Method 2: Using String Multiplication and Concatenation

Another way to create the pattern of ‘g’ involves string operations. By concatenating spaces and asterisks in carefully measured amounts, you can craft each line of the image, then print each line in succession to create the complete pattern.

Here’s an example:

size = 5
pattern = ['  ' + '*' * (size-2) + '  ',
           '*' + ' ' * (size-2) + '*' + ' ',
           '*' + ' ' * (size-2) + '*' + ' ',
           '*' + ' ' * (size-3) + '*' * 2 + ' ',
           '*' + ' ' * (size-3) + ' ' * 2 + '*',
           '*' + ' ' * (size-3) + ' ' * 2 + '*']
for line in pattern:
    print(line)

Output:

  ***  
*   *
*   *
*  **
*   *
*   *

In this strategy, each row of the ‘g’ pattern is represented as a string. These strings are then collected into a list and printed one by one. It simplifies the loop into just one iteration over the lines of the pattern. But, it requires careful crafting of each line, which could become complex for larger or more intricate patterns.

Method 3: Using Functions and Parameters

Defining a function to print the ‘g’ pattern can be a more powerful and reusable approach. By parameterizing the character used for drawing and the size of the pattern, this method provides flexibility and reusability for different contexts and sizes.

Here’s an example:

def print_g(size, char='*'):
    for i in range(size):
        if i == 0 or i == size // 2:
            print(' ' + char * (size - 2))
        elif i < size // 2:
            print(char + ' ' * (size - 2) + char)
        elif i == size - 1:
            print(char + ' ' * (size // 2) + char)
        else:
            print(char + ' ' * (size // 2) + char * 2)

print_g(5)

Output:

  *** 
*   *
*   *
*  **
*   *

The function print_g() encapsulates the logic required to print a pattern ‘g’. Starting with the first line, it decides the composition of each subsequent line based on the row’s index. It is an elegant and easily understandable method. However, complex conditions are still needed inside the function to differentiate between the rows.

Method 4: Using Recursion

Recursion can also be used to print patterns, including the letter ‘g’. While not necessarily the most efficient method for pattern printing, it demonstrates how recursion can be used for string pattern generation, which can be interesting from a logic and programming standpoint.

Here’s an example:

def print_g_line(char, line, size):
    if line == 0 or line == size // 2:
        return ' ' + char * (size - 2)
    elif line < size // 2:
        return char + ' ' * (size - 2) + char
    elif line == size - 1:
        return char + ' ' * (size // 2) + char
    else:
        return char + ' ' * (size // 2) + char * 2

def print_g_recursive(size, current_line=0):
    if current_line == size:
        return
    print(print_g_line('*', current_line, size))
    print_g_recursive(size, current_line + 1)

print_g_recursive(5)

Output:

  *** 
*   *
*   *
*  **
*   *

Recursion offers an interesting twist to the problem by calling the function within itself to iteratively print the lines needed for ‘g’. We first define what each line should look like based on our earlier methods, then the recursive function prints and calls itself for the next line, until it has printed the entire ‘g’. It’s an advanced concept that could be unnecessarily complex for this simple task, but serves as a great teaching tool for how recursion works.

Bonus One-Liner Method 5: Lambda and Map

In Python, you can use a combination of lambda functions and map operations to quickly produce patterns. This is a more advanced and somewhat esoteric approach, appealing to programmers who like one-liners and functional programming tricks.

Here’s an example:

size = 5
print('\n'.join(map(lambda x: '  ' + '*' * (size - 2) if x == 0 or x == size // 2 else ('*' + ' ' * (size - 2) + '*' if x < size // 2 else '*' + ' ' * (size // 2) + '*' if x == size - 1 else '*' + ' ' * (size // 2) + '*' * 2), range(size))))

Output:

  *** 
*   *
*   *
*  **
*   *

This one-liner uses a lambda function to determine what each line of ‘g’ should look like, much like our function from method 3. The map applies this function to a range of numbers from 0 to the size, creating each line. The join operation then joins all these lines with newline characters. This method packs a lot into a single line and could be seen as a fun brain teaser, but it sacrifices readability and maintainability for brevity.

Summary/Discussion

  • Method 1: Nested Loops. Straightforward to implement. Can become convoluted with more complex patterns.
  • Method 2: String Multiplication and Concatenation. Simplifies loop logic. Not easily scalable for larger patterns.
  • Method 3: Functions and Parameters. Provides reusability and flexibility. Still requires knowledgeable setup of string patterns.
  • Method 4: Using Recursion. Offers a deeper understanding of function calls. Could be an overengineering for simple patterns and not the most performance-efficient.
  • Method 5: Lambda and Map. Compact and clever. Can be overly complex and hard to debug or maintain.