Creating a Hollow Triangle Pattern with Python: A Step-by-Step Guide
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Chapter 1: Introduction to Hollow Triangles
In this guide, we will explore how to write a Python function named hollow_triangle(string) that generates a hollow triangle pattern using characters from a given string.
To illustrate the concept, let's consider the string string = "abcdefghijkl".
a
b lc k
defghij
When the input string is string = "abcdefghij", the output will resemble:
a
b *c *
defghij
In cases where the string does not contain enough characters to create a full triangle, we will fill in the missing spaces with * characters. This solution assumes that the input will consist solely of alphabetic characters and will contain a minimum of seven characters.
Here’s what the triangle looks like with different string lengths:
- For string = "abcdefgh":
a
b h
cdefg
- For string = "abcdefg":
a
b *
cdefg
- For string = "abcdefghijklmnop":
a
b pc o
d n
efghijklm
- For string = "abcdefghijklmn":
a
b *c *
d n
efghijklm
Before diving into the solution, take a moment to attempt this challenge on your own!
Getting to the Answer
To determine if a string can form a perfect triangle, we need to consider its length.
- For string = "abcdefgh" (8 characters):
a
b h
cdefg
- For string = "abcdefghijkl" (12 characters):
a
b lc k
defghij
- For string = "abcdefghijklmnop" (16 characters):
a
b pc o
d n
efghijklm
From these examples, we observe that strings whose lengths are multiples of 4 can create perfect triangles.
Thus, the initial step is to pad the string with * characters to ensure its length becomes a multiple of 4:
- abcdefg becomes abcdefg*
- abcdefgh remains unchanged as it already has 8 characters (a multiple of 4).
- abcdefghi becomes abcdefghi***
- abcdefghij becomes abcdefghij**
- abcdefghijk becomes abcdefghijk*
- abcdefghijkl remains unchanged as it has 12 characters (also a multiple of 4).
- abcdefghijklm becomes abcdefghijklm***, and so forth.
This padding guarantees that the string's length will be a multiple of 4, enabling it to form a perfect triangle.
Next, we can compute the height of the triangle based on the string length:
length height
8 3
12 4
16 5
20 6
The formula for height is height = length // 4 + 1.
For example, with string = "abcdefghijklmnop":
a # top line
b pc o
d n
efghijklm # bottom line
Splitting the Triangle
The triangle can be divided into three parts:
- Top Line: Contains only the first character.
- Middle Lines: Utilizes a loop to print the characters.
- Bottom Line: Displays the remaining unused characters.
Here’s a closer look at the middle lines:
b p # 3 spaces + string[1] + 1 space + string[-1]
c o # 2 spaces + string[2] + 3 spaces + string[-2]d n # 1 space + string[3] + 5 spaces + string[-3]
The Answer
Here is the implementation of the function:
def hollow_triangle(string):
# If string length is not a multiple of 4
if len(string) % 4 > 0:
# Pad with * until string length is a multiple of 4
string += '*' * (4 - len(string) % 4)
# Finding height of triangle
height = len(string) // 4 + 1
# Printing top line
print((height - 1) * ' ', string[0], sep='')
# Printing middle lines using a loop
for i in range(1, height - 1):
print((height - i - 1) * ' ', string[i], ' ' * (2 * i - 1), string[-i], sep='')
# Printing bottom line
print(string[i + 1:-i])
Conclusion
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Chapter 2: Video Demonstrations
To further enhance your understanding of this topic, check out these informative videos:
The first video titled "Hollow Triangle (Difficult Python Practice Question 5)" provides a comprehensive walkthrough of the concept.
The second video, "Hollow Triangle (Can you Solve This in ONE Line? 9)", challenges you to find a more concise solution.