How to write a single program in python to print different triangles

Question

Asterisk pyramids or triangles

Answer 1

If you want to use the same script to print different patterns when running at different times, what you can do is write functions to print different patterns and then randomly call these functions. Refer to the example below:

import random

def pattern1():
    n = 5
    k = 2*n - 2
    for i in range(0, n): 
        for j in range(0, k): 
            print(end=" ") 
            k = k - 1
            for j in range(0, i+1):
                print("* ", end="")
            print("\r")

def pattern2():
    n = 3
    k = 2*n - 2
    for i in range(0, n): 
        for j in range(0, k): 
            print(end=" ") 
            k = k - 1
            for j in range(0, i+1):
                print("* ", end="")
            print("\r")

def pattern3():
    n = 7
    k = 2*n - 2
    for i in range(0, n): 
        for j in range(0, k): 
            print(end=" ") 
            k = k - 1
            for j in range(0, i+1):
                print("* ", end="")
            print("\r")

which=random.randint(1,3)

if which==1:
    pattern1()
elif which==2:
    pattern2()
else: 
    pattern3()

Answer 2

Hi, you can use following code snippet to print '*' asterisk triangle pattern in python:

# number of spaces k

# number of rows n = 5

k = 2*n - 2

# outer loop to handle number of rows 

for i in range(0, n): 

        # inner loop to handle number spaces 

        # values changing acc. to requirement 

        for j in range(0, k): 

            print(end=" ") 

        # decrementing k after each loop 

        k = k - 1

        # inner loop to handle number of columns 

        # values changing acc. to outer loop 

        for j in range(0, i+1):

            # printing stars 

            print("* ", end="")

        # ending line after each row 

        print("\r")

Answer 3

use nested if in response to a prompt eg

a=print("Enter 1 for pyramid or 2 for triangle")
if(a=1)
{
#enter commands for pyramid triangle
}
elif(a=2)
{
#enter commands for right angle triangle
}

Comments

Hi Brianni, you have a nice approach to print different patterns based on user input, but to store the user-input, you can't use print statement. It will simply print the statement for you, but wont store the keyboard input from user. To store keyboard input into a variable, either use raw_input() or input() methods. For eg.

a = input("What is your age? ") 

Or

a = raw_input("What is your name?")

Answer 4

Here is a program to print an '*' pyramid

def pyfunc(r):
    for x in range(r):
        print(' '*(r-x-1)+'*'*(2*x+1))    #single whitespace present in the print statement string
pyfunc(4) 

output:

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

In case you want to print triangles, to the same program you can just, in place of 1 whitespace character, insert another whitespace character or remove the present one to null string as shown below:

def pyfunc(r):
    for x in range(r):
        print('  '*(r-x-1)+'*'*(2*x+1))
pyfunc(4)

output:

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

def pyfunc(r):
    for x in range(r):
        print(''*(r-x-1)+'*'*(2*x+1))
pyfunc(4)

output:

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