CODEWITHSUNDEEP
python
Vladimir Putin
Vladimir Putin

Reputation: 701

Strange issue with global variables & for loops

I was fooling around today and decided to create a program that prints out a beach, unfortunately, it doesn't work the way I want it to. Here is the source code for it:

def beach1():
    for i in range(7):
        global beach, water, land
      (beach, water, land) = (5, 0 + 5, 35 - 5)
        print(''.join(['o' for i in range(land)])+''.join(['*' for i in  range(beach)])+''.join(['~' for i in range(water)]))
beach1()

Here is the current output:

oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~
oooooooooooooooooooooooooooooo*****~~~~~

And here is what I want it to output:

oooooooooooooooooooooooooooooo*****~~~~~
ooooooooooooooooooooooooo*****~~~~~~~~~~
oooooooooooooooooooo*****~~~~~~~~~~~~~~~
ooooooooooooooo*****~~~~~~~~~~~~~~~~~~~~
oooooooooo*****~~~~~~~~~~~~~~~~~~~~~~~~~
ooooo*****~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*****~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The reason I expect the output to change is because of the three variables, land, beach, and water. Since these variables are global, they retain their value, so every time the for loop repeats, land's value will go down by 5. Therefore the land section of the output will be printed 5 less times every time the loop repeats. Vice versa for the water section of the output. When I came up with the idea in my head, it seemed like it would work, but now it doesn't. What am I doing wrong? All help is appreciated, thanks! Also, if you can come up with a better title, feel free to, I certainly can't.

Upvotes: 0

Views: 76

Answers (2)

Mike McKerns
Mike McKerns

Reputation: 35247

you could also make your prints simpler…

>>> for i in range(1,8):
...     print('%s%s%s' % ('o'*5*(7-i), '*'*5, '~'*5*(i)))
... 
oooooooooooooooooooooooooooooo*****~~~~~
ooooooooooooooooooooooooo*****~~~~~~~~~~
oooooooooooooooooooo*****~~~~~~~~~~~~~~~
ooooooooooooooo*****~~~~~~~~~~~~~~~~~~~~
oooooooooo*****~~~~~~~~~~~~~~~~~~~~~~~~~
ooooo*****~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*****~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Upvotes: 2

julienc
julienc

Reputation: 20355

The problem is that you're setting the size of your 3 areas with this:

(beach, water, land) = (5, 0 + 5, 35 - 5)

Which is a constant value, so it won't change during the for loop!

Juste make the values depend on i, like this:

for i in range(8):
    (beach, water, land) = (5, 5+5*i, 35-5*i)

Moreover, you are using the same variable, i, for your main loop and your inner loops on line 5. You have to rename one of them!

Upvotes: 2

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