Given a String List, the following program returns a concatenated list of all its string elements with its alternate elements reversed.
Input : test_str = ‘geeksgeeks best for geeks’
Output : skeegskeeg best rof geeks
Explanation : Alternate words reversed.
Input : test_str = ‘geeksgeeks best geeks’
Output : skeegskeeg best skeeg
Explanation : Alternate words reversed.
Method 1 : Using reversed() and loop
In this, we perform the task of reversing strings using reversed() and then check for alternates using % operator and concatenate accordingly.
Python3
# initializing stringtest_str = 'geeksgeeks is best for geeks' # printing original stringprint("The original string is : " + str(test_str)) # spliting string temp = test_str.split() res = []for idx in range(len(temp)): # reversing if alternate if idx % 2 == 0: res.append(''.join(list(reversed(temp[idx])))) else : res.append(temp[idx]) res = ' '.join(res) # printing result print("Transformed String : " + str(res)) |
Output:
The original string is : geeksgeeks is best for geeks
Transformed String : skeegskeeg is tseb for skeeg
Method 2 : Using slicing and list comprehension
In this, we perform task fo reversal using slicing and then list comprehension is used to perform the task done by loop, in shorthand.
Python3
# initializing stringtest_str = 'geeksgeeks is best for geeks' # printing original stringprint("The original string is : " + str(test_str)) # spliting string temp = test_str.split() # list comprehension to solve problem in 1 linerres = ' '.join([''.join(list(reversed(temp[idx]))) if idx % 2 == 0 else temp[idx] for idx in range(len(temp))]) # printing result print("Transformed String : " + str(res)) |
Output:
The original string is : geeksgeeks is best for geeks
Transformed String : skeegskeeg is tseb for skeeg
Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.
To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.
