🔒 Help with understanding the code

[tranquil zodiac]

Hello, I don't really understand this code (especially the second and third for loop and how the print function does here)

[inland delta]

@tranquil zodiac

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[tranquil zodiac]

steps = int(input("Enter the number of steps for the Christmas tree: "))

for i in range(1, steps + 1):
    for j in range(steps - i):
        print(" ", end="")
    

    for s in range(2 * i - 1):
        print("-", end="")
    
    print()

this is the code

[pale nova]

ok what do you understand about this code so far?

[tranquil zodiac]

I understand that the input and then the first for loop where it starts at 1 (so it doesnt start at 0) and then ends at the number + 1

so that if you go from 1-4

you dont want it to stop counting at 3

idk if im making sense

[pale nova]

ok cool

[neon jay]

!e

steps = 5

for i in range(1, steps + 1):
    for j in range(steps - i):
        print(".", end="")
    

    for s in range(2 * i - 1):
        print("-", end="")
    
    print()

this might give some perspective

[pale nova]

so what do you think of the 2nd loop?

[inland delta]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

001 | ....-
002 | ...---
003 | ..-----
004 | .-------
005 | ---------

[tranquil zodiac]

I don't really understand it

I don't get the steps-i

[pale nova]

so if steps is 3 and i is the running number like the starting number 1, then steps-i is 3 - 1

[tranquil zodiac]

yeah but each time its reducing the value of j right?

so like after 3-1

its going to be 3-2

and so on

but isnt that not whats supposed to happen?

as in it's supposed to increase the number instead of decrease it?

[pale nova]

!e

steps = 5

for i in range(1, steps + 1):
    print(f"{i=} {steps=} {steps-i=} {2 * i - 1=}")
    for j in range(steps - i):
        print(".", end="")
    

    for s in range(2 * i - 1):
        print("-", end="")
    
    print()

[inland delta]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

001 | i=1 steps=5 steps-i=4 2 * i - 1=1
002 | ....-
003 | i=2 steps=5 steps-i=3 2 * i - 1=3
004 | ...---
005 | i=3 steps=5 steps-i=2 2 * i - 1=5
006 | ..-----
007 | i=4 steps=5 steps-i=1 2 * i - 1=7
008 | .-------
009 | i=5 steps=5 steps-i=0 2 * i - 1=9
010 | ---------

[tranquil zodiac]

wait so

[pale nova]

no that's supposed to happen. So you can do range(n) and it will only loop in that range

[tranquil zodiac]

ok

but then it multiplies it

[pale nova]

So in the first iteration, steps-i = 4.

So you can see it as

for j in range(4):

[pale nova]

Do you know you can multiply a string?

!e

print("rat" * 3)

[inland delta]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

ratratrat

[tranquil zodiac]

Ok

I get what’s happening so far

[tranquil zodiac]

Yeah

But how does it maintain the tree shape then ?

[pale nova]

☝️

The 2nd loop adds spaces

The 3rd loop makes the tree (dashes)

In the first iteration, it would make 4 spaces and 1 dash

In the 2nd iteration, it would make 3 spaces and 2 dashes

etc

[lunar patrol]

i think u know what end="" does?? it doesnt make \n

[pale nova]

\n means new line

[inland delta]

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