[Python] Enumerate a string to substrings

Today I’d like to show you a quick hint that might be obvious, but it took useful, it’s about the enumeration of string to substrings.

You probably know the deffinition of a substring, so Y is a substring for X if: X = U.Y.V

	#!/usr/bin/env python
	#! -- coding: utf-8 --

	# Enumerate a string to substrings
	# Y is a substring for X if: X = U.Y.V


	def enumerate(string):
	"""Function that will enumerate a string to substring
	return: A list with all the substrings

	>>> enumerate(aabccb)
	result = ( , a, c, b, abcc, abc, bc, cc, cb, aabc, aab, bccb, aa, bcc, ab, abccb, aabcc, aabccb, ccb)
	"""
	prefix = list()
	root = list()
	suffix = list()
	result = list()

	for i in range(len(string)):
	prefix.append(string[:i])
	root.append(string[i:])
	root.append(string[:i])
	suffix.append(string[:i])

	for j in range(len(string)):
	prefix.append(string[i:j])
	root.append(string[j:])
	root.append(string[i:j])

	# Append prefix, root and suffix to the result list
	result.extend(prefix)
	result.extend(root)
	result.extend(suffix)

	# Sort the result list
	result.sort(key = len)

	# Return the result list without duplicate substrings
	return list(set(result))


	if __name__ == '__main__':
	string = "aabccb"
	print "String to enumerate:", string
	print "Substrings:", ', '.join(map(str, enumerate(string)))

Enjoy !

Boubakr Tech