Graph generator for looking at functions as mentioned in standupmaths' "Four has Four Letters"

graph_generator.py

def create_graph(classification_function, values, highlight_fixed_points=True):
	connections = {}
	for n in values:
		if n not in connections.keys():
			connections[n] = classification_function(n)

	fixed_points = [item[0] for item in connections.items() if item[0] == item[1]]

	fixed_point_styles = ['\t{0} [style=filled, fillcolor=red, fontcolor=white, fontsize=30];'.format(fixed_point) for fixed_point in fixed_points if highlight_fixed_points]
	relationships = ['\t{0} -> {1}'.format(item[0], item[1]) for item in connections.items()]

	dot_file_text = (
		'digraph {{\n'
		'\toverlap=false;\n'
		'\tsplines=true;\n'
		'\tdpi=300;\n'
		'{0}\n'
		'{1}\n'
		'}}'
	).format('\n'.join(fixed_point_styles), '\n'.join(relationships))

	return dot_file_text

def main():
	def binary_letter_count(n):
		"""
			Number of characters in binary string
			i.e. 1001 -> one zero zero one -> 14
		"""
		binary = '{0:b}'.format(n)
		binary_text = binary.replace('0', 'zero').replace('1', 'one')
		return len(binary_text)

	def decimal_letter_count(n):
		"""
			Number of characters in naive decimal string
			i.e 134 -> one three four -> 12
		"""
		DIGITS = {
			'0': 'zero',
			'1': 'one',
			'2': 'two',
			'3': 'three',
			'4': 'four',
			'5': 'five',
			'6': 'six',
			'7': 'seven',
			'8': 'eight',
			'9': 'nine'
		}

		decimal_text = str(n)
		for digit in DIGITS:
			decimal_text = decimal_text.replace(digit, DIGITS[digit])

		return len(decimal_text)

	def sum_digits_squared(n):
		"""
			Square each of the digits of the number and sum them
		"""
		return sum([int(x) ** 2 for x in str(n)])

	# Just change the function you want to graph here and the range of values you want to graph it for,.
	dot_file_text = create_graph(binary_letter_count, range(0, 101))
	
	with open('graph.dot', 'w') as f:
		f.write(dot_file_text)

if __name__ == '__main__':
	main()