Python | Sort words of sentence in ascending order

Given a sentence, sort it alphabetically in ascending order. 

Examples:

Input : to learn programming refer geeksforgeeks
Output : geeksforgeeks learn programming refer to

Input : geeks for geeks
Output : for geeks geeks

Approach 1 : We will use the built-in library function to sort the words of the sentence in ascending order. 

Prerequisites:

• split()
• sort() in Python
• join()

Follow the steps below:

• Split the Sentence in words.
• Sort the words alphabetically
• Join the sorted words alphabetically to form a new Sentence.

Below is the implementation of the above idea.

Python3

# Function to sort the words
# in ascending order


def sortedSentence(Sentence):

    # Splitting the Sentence into words
    words = Sentence.split(" ")

    # Sorting the words
    words.sort()

    # Making new Sentence by
    # joining the sorted words
    newSentence = " ".join(words)

    # Return newSentence
    return newSentence

# Driver's Code


Sentence = "to learn programming refer geeksforgeeks"
# Print the sortedSentence
print(sortedSentence(Sentence))

Sentence = "geeks for geeks"
# Print the sortedSentence
print(sortedSentence(Sentence))

Output

geeksforgeeks learn programming refer to
for geeks geeks

Time Complexity : O(nlogn) , due to built-in sort function used.
Auxiliary Space : O(n) , where n is the total number of characters in string. 

Approach – 2 : 

In this approach we will use the built-in split() method alongside the sorted() function to achieve the same in less lines and less use of functions and methods. We will not use the join() method here.

Python3

def sort_alphabetically(sentence : str) -> list():

  s = sentence.split(" ")

  return sorted(s)


sen = "to learn programming refer geeksforgeeks"
print(sort_alphabetically(sen))

sen = "geeks for geeks"
print(sort_alphabetically(sen))

Output

['geeksforgeeks', 'learn', 'programming', 'refer', 'to']
['for', 'geeks', 'geeks']

Time Complexity – O(nlogn) # Due to the use of sorted() built in function.
Space Complexity – O(n) # ‘n’ number of characters in string