I am coding an shore line generator but something is not right with my code. I have a old code like this:

import random
import time

def land_errosion():
    
    continent = [[0,0,0,0,0,0,0,0,0,0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,'*','*','*','*','*','*','*','*',0],
                 [0,0,0,0,0,0,0,0,0,0]]

    for row in range(8):
        for square in range(9):

            if continent[row][square] == 0:

                if continent[row][square + 1] != 0:
                    continent[row][square + 1] = random.choice([0, continent[row][square+1]])

                elif continent[row + 1][square] != 0:
                    continent[row + 1][square] = random.choice([0, continent[row+1][square]])

            if continent[row][square] != 0:

                if continent[row][square+1] == 0 or continent[row+1][square] == 0:
                    continent[row][square] = random.choice([0, continent[row][square]])


    for row in range(9):
        for square in range(10):
            print(continent[row][square], end=' ')
        print()
    print()


if __name__ == '__main__':
    print(f"--- {t1/1000000000} seconds ---")

And this is the new code. The differences are the new one uses for loops to create land while the old one use fixed pattern:

import random
import time


def land_errosion():

    continent = []

    sea_n = []

    for i in range(10):
        sea_n.append(0)

    land_row = [0]
    for i in range(8):
        land_row.append('*')
    land_row.append(0)

    continent.append(sea_n)
    for i in range(8):
        continent.append(land_row)
    continent.append(sea_n)

    for verti in range(9):
        for hori in range(9):

            if continent[verti][hori] == 0:

                if continent[verti][hori + 1] != 0:
                    continent[verti][hori + 1] = random.choice([0, continent[verti][hori + 1]])

                elif continent[verti + 1][hori] != 0:
                    continent[verti + 1][hori] = random.choice([0, continent[verti + 1][hori]])

            if continent[verti][hori] != 0:

                if continent[verti][hori + 1] == 0 or continent[verti + 1][hori] == 0:
                    continent[verti][hori] = random.choice([0, continent[verti][hori]])

     for verti in range(10):
         for hori in range(10):
             print(continent[verti][hori], end=' ')
         print()
     print()

if __name__ == '__main__':

    land_errosion()
    

I don’t change the main code for create shore line but the output is totally different:

the old code:

0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 * * 0 0 * * * 0 
0 0 * * * * * * * 0 
0 0 * * * * * * 0 0 
0 0 0 * * * * * * 0 
0 * * * * * * * * 0 
0 0 * 0 * * * * 0 0 
0 0 0 0 0 0 0 0 0 0 

the new code:

0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 

I don’t understand why, someone can point me the problems?