How can I slice a smaller array into an N x M array if I know the point of insertion?
ie,
# Larger array
[1,1,1,1,1,1,1,1,1,1]
[1,1,1,1,1,1,1,1,1,1]
[1,1,1,1,1,1,1,1,1,1]
# Smaller array
[1,2,3,4]
[5,6,7,8]
# Insert at [1,6] gives:
[1,1,1,1,1,1,1,1,1,1]
[1,1,1,1,1,1,1,2,3,4]
[1,1,1,1,1,1,5,6,7,8]
And using just list comprehensions?
l = [[1,1,1,1,1,1,1,1,1,1],
[1,1,1,1,1,1,1,1,1,1],
[1,1,1,1,1,1,1,1,1,1]]
s = [[1,2,3,4],
[5,6,7,8]]
def insert(large, small, row, col):
for i, r in enumerate(small):
large[row + i][col:col + len(r)] = r
insert(l, s, 1, 6)
print(l)
This outputs:
[[1, 1, 1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 2, 3, 4], [1, 1, 1, 1, 1, 1, 5, 6, 7, 8]]
If you are happy to use a 3rd party library, NumPy offers a generic solution for arbitrary coordinates:
i, j = (1, 6)
x[i:i+a.shape[0], j:j+a.shape[1]] = a
print(x)
array([[1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1, 1, 2, 3, 4],
[1, 1, 1, 1, 1, 1, 5, 6, 7, 8]])
