I want to put values in the top, bottom, left and right of a particular element that is a multidimensional array.

What should I do to make the data I expect like the one below?

#Target Data
test_list = [
    ['.', '.', '.'],
    ['.', '#', '.'],
    ['.', '.', '.']
]


# expected data
test_list = [
    ['.', '#', '.'],
    ['#', '#', '#'],
    ['.', '#', '.']
]

Below are some of the actions I've tried.
However, some of the expected values are not substituted, and the extra values are substituted.

We are unable to find a solution at this stage, so if anyone knows, please let us know.

#Target Data
test_list = [
    ['.', '.', '.'],
    ['.', '#', '.'],
    ['.', '.', '.']
]

for i in range(len(test_list))):
    for jin range(len(test_list))):
        try:
            if test_list[i][j+1]=='#' or test_list[i][j-1]=='#' or test_list[i-1][j]=='#' or test_list[i+1][j]=='#':
                test_list[i][j]='#'
        except IndexError:
            pass
print(test_list[0])
print(test_list[1])
print(test_list[2])

# output result
['.', '#', '.']
['#', '#', '.']
['#', '#', '.']

python python3

2022-09-30 19:34

3 Answers

The script binary_dilation() is easy.
scipy.ndimage.binary_dilation—SciPy Manual

import numpy as np
from scope.ndimage import binary_dilation

default_closs(lst,s):
    arr = np.array(lst)
    arr [binary_dilation(arr==s)] = s
    return ar.tolist()

2022-09-30 19:34

Considering the possibility of multiple #, how about the following code?

test_list=[
    ['.', '.', '.'],
    ['.', '#', '.'],
    ['.', '.', '.']
]

indexes = [ ]
for i in range(len(test_list))):
    for jin range (len(test_list[0])):
        if test_list[i][j]=="#":
            indexes.append(i-1,j))
            indexes.append(i,j-1))
            indexes.append(i,j+1))
            indexes.append(i+1,j))
            
for(i,j)in indexes:
    try:
        test_list[i][j]="#"
    except IndexError:
        pass
print(test_list)

2022-09-30 19:34

If you don't mind using numpy,

def set_closs(lst,s):
    import numpy as np
    ary=np.array(lst)
    for idx in zip (*np.where(ary==s)):
        aary [max(0,idx[0]-1): idx[0]+2,idx[1]]=ary [idx]
        ary [idx[0], max(0, idx[1]-1): idx[1]+2] = ary [idx]
    returnary.tolist()

# Target Data
test_list = [
    ['.', '.', '.'],
    ['.', '#', '.'],
    ['.', '.', '.']
]

out_list = set_closs(test_list, '#')
print(*out_list, sep='\n')
"""
['.', '#', '.']
['#', '#', '#']
['.', '#', '.']
"""

test_list = [
    ['.', '.', '.', '.'],
    ['.', '#', '.', '.'],
    ['.', '.', '#', '.'],
    ['.', '.', '.', '.']
]
out_list = set_closs(test_list, '#')
print(*out_list, sep='\n')
"""
['.', '#', '.', '.']
['#', '#', '#', '.']
['.', '#', '#', '#']
['.', '.', '#', '.']
"""

2022-09-30 19:34

If you have any answers or tips

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