Accessing 2D Array Elements

To reach one cell of a 2D array, use two indices: the first picks the row, the second picks the column inside that row. Both start at 0.

var level := [
	[1, 1, 1, 1],
	[1, 0, 2, 1],
	[1, 1, 1, 1]
]
print(level[1][2]) # 2 (row 1, column 2)
print(level[0][0]) # 1

level[1] returns the row [1, 0, 2, 1], and [2] then picks index 2 of that row. Negative indices count from the end, as in any array: level[-1][-1] is the bottom-right cell.

Assign to a cell to change it. When the player picks up the coin, its tile becomes floor:

level[1][2] = 0
print(level[1]) # [1, 0, 0, 1]

An index outside the grid is an error that stops the program: level[3][0] fails because the rows go from 0 to 2. When the indices come from input or from a calculation, check them against the size of the grid first:

var row := 2
var col := 5
if row >= 0 and row < level.size() and col >= 0 and col < level[row].size():
	print(level[row][col])
else:
	print("Outside the map")

This prints Outside the map, because column 5 does not exist. and stops at the first condition that is false, so level[row] is only read when the row exists.