How to generate a hollow hourglass pattern with numbers in Python
We can generate different patterns in Python once we have a strong grip over the concepts involving loops.
In this shot, we will use for loops and numbers to generate a hollow hourglass pattern.
Description
We will use 2 for loops (one for the upper half and the other for the lower half of the hollow hourglass) that contain 2 nested for loops to generate an hourglass pattern.
Code
Let’s look at the code snippet below.
# Number of Rows
row = 5
# Upper-Half
for i in range(row, 0, -1):
for j in range(row-i):
print(" ", end="")
for j in range(1, 2*i):
if i==1 or i==row or j==1 or j==2*i-1:
print(i, end=" ")
else:
print(" ", end=" ")
print()
# Lower-Half
for i in range(2, row+1):
for j in range(row-i):
print(" ", end="")
for j in range(1, 2*i):
if i==1 or i==row or j==1 or j==2*i-1:
print(i, end=" ")
else:
print(" ", end=" ")
print()Explanation
-
In line 2, we set the number of rows to
5(i.e. the length of the hourglass). -
In lines 5-13, we use the first outer
forloop to print the upper half of the hourglass. -
In lines 6-7, we use the
forloop to create the spaced-alignment. -
In lines 8-13, we use another
forloop to print the upper pattern.- We print
i, asidecreases with every increase in the row number in the upper half of the hourglass. end = ""in the print statement is used to stay on the same line.- The
print()statement is used to move to the next line.
- We print
-
In lines 16-24, we use the second outer
forloop to print the lower half of the hourglass. -
In lines 17-18, we use the
forloop to create the spaced-alignment. -
In lines 19-24, we use another
forloop to print the lower pattern.- We print
i, asiincreases with every increase in the row number in the lower half of the hourglass. end = ""in the print statement is used to stay on the same line.- The
print()statement is used to move to the next line.
- We print
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