I would like to define a function that prints output of a triangle like this, when number of rows = 5.

*
 *
* *
 * *
* * *

currently, my code looks like this:

def triangle(n):
    result = ''
    
    for i in range(1, n 1):
        result  = ('*' * i) '\n'
    return result

however, it's not the way i want it to look. any ideas how I can improve this?

CodePudding user response：

To produce this exact output -

*
 *
* *
 * *
* * *

You can do it this way -

def triangle(n):
    result = ''
    
    for i in range(1, n 1):
        if i % 2 == 0:
            result  = ' '
        result  = ('* ' * (i//2   i%2)) '\n'
    return result

CodePudding user response：

This will work for you.

def triangle(n):
result = ''

for i in range(1, n 1):
    line = ('*' * i) '\n'
    result = result line ' ' line
return result

The main idea here is you have a result for a corresponding line in line. You need the same line with space prepended to it with the previous result. thus the new code in the loop.

CodePudding user response：

Here are some fun ways to solve this problem, learning a few python tricks in the process

one liner

Here is a one liner solution, it uses multiplication and slicing of the pattern to produce the output and joins the lines:

pat = ' *'
n = 5
print('\n'.join((pat*((i 1)//2))[-i:] for i in range(1, 1 n)))

output:

*
 *
* *
 * *
* * *

using an infinite iterator (and a classical loop):

from itertools import cycle
c = cycle('* ')
result = ''
l = ''
for i in range(5):
    l = next(c) l
    result =l '\n'
print(result)

using itertools.cycle and itertools.accumulate

from itertools import cycle, accumulate
c = cycle('* ')
print('\n'.join(map(lambda x: x[::-1], accumulate(next(c) for i in range(5)))))