Python - Test String in Character List and vice-versa
Given a String, check if it's present in order in the character list and vice versa.
Input : test_str = 'geeks', K = ['g', 'e', 'e', 'k', 'f', 'o', 'r', 'g', 'e', 'e', 'k', 's'] [ String in Character list ]
Output : True
Explanation : geeks is present in list , starting from 7th index till end.Input : test_str = 'geeksforgeeks', K = ['g', 'e', 'e', 'k', 's'] [Character list in String]
Output : True
Explanation : ['g', 'e', 'e', 'k', 's'] present in string, starting from the beginning of string.
Method #1: Using in operator + join() [ String in character list ]
In this, we convert the character list to a string using join() and apply it in the operator to test for substring presence.
# Python3 code to demonstrate working of
# Test String in Character List and vice-versa
# Using in operator and join() [String in list]
# initializing string
test_str = 'geeks'
# printing original string
print("The original string is : " + str(test_str))
# initializing Character list
K = ['g', 'e', 'e', 'k', 'f', 'o', 'r', 'g', 'e', 'e', 'k', 's']
# joining list
joined_list = ''.join(K)
# checking for presence
res = test_str in joined_list
# printing result
print("Is String present in character list : " + str(res))
Output
The original string is : geeks Is String present in character list : True
Time Complexity: O(n)
Auxiliary Space: O(n)
Method #2 : Using in operator + join() [ Character List in String ]
In this, the target character list is converted to String and then checked in String using in operator.
# Python3 code to demonstrate working of
# Test String in Character List and vice-versa
# Using in operator + join() [ Character List in String ]
# initializing string
test_str = 'geeksforgeeks'
# printing original string
print("The original string is : " + str(test_str))
# initializing Character list
K = ['g', 'e', 'e', 'k', 's']
# joining list
joined_list = ''.join(K)
# checking for presence
res = joined_list in test_str
# printing result
print("Is character list present in String : " + str(res))
Output
The original string is : geeksforgeeks Is character list present in String : True
Time Complexity: O(n) -> as join method takes O(n) complexity
Auxiliary Space: O(n)
Method 3 : using the set() function and intersection() method
Step-by-step approach:
- Initialize the original string and print it.
- Initialize the character list.
- Convert the character list to a set using the set() function.
- Get the intersection of the character set and the set of the original string using the intersection() method.
- Check if the length of the intersection set is equal to the length of the character set.
- Print the result.
# Python3 code to demonstrate working of
# Test String in Character List and vice-versa
# Using set() and intersection() [ Character List in String ]
# initializing string
test_str = 'geeksforgeeks'
# printing original string
print("The original string is : " + str(test_str))
# initializing Character list
K = ['g', 'e', 'e', 'k', 's']
# converting list to set
char_set = set(K)
# getting intersection of sets
intersect_set = char_set.intersection(set(test_str))
# checking if all characters are present
res = len(intersect_set) == len(char_set)
# printing result
print("Is character list present in String : " + str(res))
Output
The original string is : geeksforgeeks Is character list present in String : True
Time complexity: O(n), where n is the length of the original string.
Auxiliary space: O(k), where k is the length of the character list.
