Printing out all the permutations of string

How to generate permutation of a given string where digits are kept as it is, but alphabets are replaced by lower and upper case characters

	#! /usr/env/path python
	def helper(string, result, index , slate):
	if (len(string) == len(slate)):
	result.append(slate)
	return
	if(string[index].isdigit()):
	slate = slate + str(string[index])
	helper(string, result, index+1, slate)
	slate = slate[:-1]
	else:
	slate= slate + str(string[index].upper());
	helper(string, result, index+1, slate)
	slate = slate[:-1]
	slate = slate + str(string[index].lower())
	helper( string, result, index+1, slate)
	result =[]
	helper("a1b2",result, 0 , "")
	print(result)

view raw letterPermutationSort.py hosted with ❤ by GitHub

The above solution uses immutable strings so its not efficient time complexity-wise below solution replaces string with list

	#! /usr/env/path python
	''' This solution is done using list and removes the immutable
	string to avoid extra burden on time '''
	def solutions():
	result=[]
	def helper(index,slate=None):
	if slate== None:
	slate=[]
	if len(slate) == bag_len:
	result.append(''.join(slate))
	return
	if(bag[index].isdigit()):
	slate.append(bag[index])
	helper(index+1, slate)
	slate.pop()
	else:
	slate.append(str(bag[index].upper()))
	helper(index+1,slate)
	slate.pop()
	slate.append(str(bag[index].lower()))
	helper(index+1, slate)
	slate.pop()
	slate1 = list()
	bag = list("a1b2c3")
	bag_len = len(bag)
	helper( 0, slate1)
	print(result)
	solutions()

view raw strinnum.py hosted with ❤ by GitHub