This is a suggestion for how to have 2d collision detection in PyGame

Blob - map suggestion

# This is a suggestion to how to have 2d collision detection
# Inspired by Sentdex - part 20 intermediate Python tutorial


WIDTH  = 600
HEIGHT = 400

blob_or_zero = [[ 0 for i in range(WIDTH) ] for i in range(HEIGHT) ]	# Making a 2d blob-map, which has the same ratio as the screens pixel-map	
blobs = [ Blob( random.x, random.y ) for i in range(20) ]		# Initializing 20 blobs to random position
		
for blob in blobs:							# Placing initialized blobs in blob-map
	if not blob_or_zero[ blob.x ][ blob.y ]:			# If there are no blobs already there
		blob_or_zero [ blob.x ][ blob.y ]  =  blob
	
while running:								# GAME LOOP
									# Update blobs position and detects collision
	for blob in blue_blobs:
		blob_or_zero[ blob.x ][ blob.y ] = 0                	# Zero blob-map x and y coordinate before the move

		blob.move()					   	# Move the blob to a new position x, y

		if not blob_or_zero[ blob.x ][ blob.y ]:		# If there are no blobs at the new position
			blob_or_zero [ blob.x ][ blob.y ]  =  blob      # Insert this blob to new position

		else:
			other_blob = blob_or_zero [ blob.x ][ blob.y ]  # Get the other blob

			if blob.type == 'blue' and other_blob.type == 'blue': # check if other blob is blue
				pass
			else:
				blob + other_blob			# Else merge/eat the other blob.