Printing a pattern through the use of a dictionary

Question

We had to port a program from c to python. The code works but uses a dictionary to solve the problem. This doesn't feel like the right use of a dictionary. Is there a better way?

#!/usr/bin/env python3

def main():
    while True:
        height = input("Height: ")
        try:
            height = int(height)
            if height >= 0:
                break
        except:
            pass
   
    mtn={}
    space_mtn(height,mtn)
    hashs_mtn(height,mtn)
    print_mtn(height,mtn)
    
def space_mtn(height,mtn):
    
    for i in range(height):
        for j in range(2*height+2):
            mtn[i,j]=" "
    return 

def hashs_mtn(height,mtn):

    for i in range(height):
        for  j in range(height-1,height-i-2,-1):
            mtn[i,j] = '#'
    
    for i in range(height):
        for j in range(height+2,height+i+3):
            mtn[i,j] = '#'
    return

def print_mtn(height,mtn):
    
    for i in range(height):
        for j in range(height+3+i):
            print("{}".format(mtn[i,j]),end="")
        print("")
    return 

if __name__ == "__main__":
    main()

Answer 1

For how you're using it, it seems like a list of lists would make more sense than a dict. This is somewhat like a 2-dimensional array in C.

Your mtn initialization becomes:

mtn = []

You'll need to do a little more work in space_mtn to generate the sublists:

def space_mtn(height,mtn):
    for i in range(height):
        mtn.append([])             # Append an empty sublist at each level
        for j in range(2*height+2):
            mtn[-1].append(" ")    # Append a space to the end of the currently-last list
    return

Now in hash_mtn and print_mtn, just change your mtn[i,j] calls to mtn[i][j].

Now, there are lots of ways to make this code less C-like and more idiomatic python, or "Pythonic". I'll just say that it's possible (although not necessarily "best") to get equivalent functionality by replacing everything after your input while loop with one line:

print('\n'.join('{0:>{1}}  {0:{1}}'.format('#'*(i+1), height) for i in range(height)))

Answer 2

Dictionaries are great. As long as you don't care about a specific order (though there are ways of making them ordered and I believe they will be in a upcoming release of python).

In your case maybe the use of zip could be useful.