Python Program to reverses alternate strings and then concatenates all elements
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.Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.
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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))# splitting stringtemp = 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 resultprint("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))# splitting stringtemp = 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 resultprint("Transformed String : " + str(res)) |
Output:
The original string is : geeksgeeks is best for geeks
Transformed String : skeegskeeg is tseb for skeeg
