arraytogrid.py

# -*- coding: utf-8 -*-
"""ArrayToGrid.ipynb

Automatically generated by Colab.

Original file is located at
    https://colab.research.google.com/drive/1BwXneXu-gJQUN1sk_oIcQwMZh-EIxhpe

# Array to Grid

## 2D numpy Array -> Grid of Nodes
"""

import numpy as np

blocked = set()

class Node:
    def __init__(self, position):
        self.position = position  # (row, col)
        self.neighbors = []       # List of neighboring Node objects

    def __repr__(self):
        return f"Node({self.position})"

def boolean_array_to_node_dict(array):
    """
    Converts a 2D boolean numpy array into a dictionary of Node objects.
    True = blocked / invalid
    False = valid
    Each node stores its position and valid neighbors.

    Returns:
        dict: key = position tuple, value = list of neighbor positions
    """
    rows, cols = array.shape
    node_dict = {}

    # Step 1: Create Node objects for all False positions
    for r in range(rows):
        for c in range(cols):
            if not array[r, c]:  # Only create nodes for False (valid) cells
                node_dict[(r, c)] = Node((r, c))
            else:
                blocked.add((r, c))

    # Step 2: Assign neighbors for each node including diagonals
    directions = [
        (-1, 0), (1, 0), (0, -1), (0, 1),  # up, down, left, right
        (-1, -1), (-1, 1), (1, -1), (1, 1) # diagonals
    ]
    for pos, node in node_dict.items():
        r, c = pos
        for dr, dc in directions:
            nr, nc = r + dr, c + dc
            if (nr, nc) in node_dict:  # Only add neighbors that are valid nodes
                node.neighbors.append(node_dict[(nr, nc)])

    # Step 3: Convert to dictionary mapping position -> neighbor positions
    node_neighbor_dict = {pos: [neighbor.position for neighbor in node.neighbors]
                          for pos, node in node_dict.items()}

    return node_neighbor_dict

def blocked_positions(array):
    """
    Returns a set of positions (row, col) where the array has True values.
    """
    return blocked

"""## Examples"""

# Example 3x3 usage
bool_array = np.array([[False, True, False],
                       [False, False, True],
                       [True, False, False]])

node_dict = boolean_array_to_node_dict(bool_array)
for pos, neighbors in node_dict.items():
    print(f"Node {pos} has neighbors: {neighbors}")

# Example usage with previous array
blocked_set = blocked_positions(bool_array)
print("\nBlocked positions:", blocked_set)

# Example 5x5 boolean grid
bool_array = np.array([
    [False, True,  False, False, False],
    [False, False, True,  False, False],
    [True,  False, False, True,  False],
    [False, False, True,  False, False],
    [False, False, False, True,  False]
])

# Using the function from before
node_dict = boolean_array_to_node_dict(bool_array)

# Print the node dictionary
for pos, neighbors in node_dict.items():
    print(f"Node {pos} has neighbors: {neighbors}")

# Example usage with previous array
blocked_set = blocked_positions(bool_array)
print("\nBlocked positions:", blocked_set)