Given a String, extract K characters alternatively.
Input : test_str = ‘geeksgeeksisbestforgeeks’, K = 4
Output : geekksisforg
Explanation : Every 4th alternate range is sliced.
Input : test_str = ‘geeksgeeksisbest’, K = 4
Output : geekksis
Explanation : Every 4th alternate range is sliced.
Method #1 : Using loop + slicing
In this, we perform task of getting K characters using slicing, and loop is used to perform task of concatenation.
Python3
# Python3 code to demonstrate working of # Alternate K Length characters # Using loop + slicing # initializing string test_str = 'geeksgeeksisbestforgeeks' # printing original string print("The original string is : " + str(test_str)) # initializing K K = 4 res = '' # skipping k * 2 for altering effect for idx in range(0, len(test_str), K * 2): # concatenating K chars res += test_str[idx : idx + K] # printing result print("Transformed String : " + str(res)) |
Output:
The original string is : geeksgeeksisbestforgeeks Transformed String : geekksisforg
Method #2 : Using list comprehension + join()
This is similar to the above way, only difference being its one liner approach, and join() is used to perform task of convert back to string.
Python3
# Python3 code to demonstrate working of # Alternate K Length characters # Using list comprehension + join() # initializing string test_str = 'geeksgeeksisbestforgeeks' # printing original string print("The original string is : " + str(test_str)) # initializing K K = 4 # slicing K using slicing, join for converting back to string res = ''.join([test_str[idx : idx + K] for idx in range(0, len(test_str), K * 2)]) # printing result print("Transformed String : " + str(res)) |
Output:
The original string is : geeksgeeksisbestforgeeks Transformed String : geekksisforg
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