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Python program to find uncommon words from two Strings

  • Difficulty Level : Easy
  • Last Updated : 21 Aug, 2020

Given two sentences as strings A and B. The task is to return a list of all uncommon words. A word is uncommon if it appears exactly once in any one of the sentences, and does not appear in the other sentence.

Note: A sentence is a string of space-separated words. Each word consists only of lowercase letters.

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Input : A = "Geeks for Geeks" 
        B = "Learning from Geeks for Geeks"
Output : ['Learning', 'from']

Input : A = "apple banana mango" 
        B = "banana fruits mango"
Output : ['apple', 'fruits']

Approach: Every uncommon word occurs exactly once in any one of the strings. So, we make a hash to count the number of occurrences of every word, then return a list of words that occurs exactly once.

Below is the implementation of the above approach:

# Python3 program to find a list of uncommon words
# Function to return all uncommon words
def UncommonWords(A, B):
    # count will contain all the word counts
    count = {}
    # insert words of string A to hash
    for word in A.split():
        count[word] = count.get(word, 0) + 1
    # insert words of string B to hash
    for word in B.split():
        count[word] = count.get(word, 0) + 1
    # return required list of words
    return [word for word in count if count[word] == 1]
# Driver Code
A = "Geeks for Geeks"
B = "Learning from Geeks for Geeks"
# Print required answer
print(UncommonWords(A, B))
['from', 'Learning']

Another way to solve this problem:

def uncommon(a,b):
    list_a = a.split()
    list_b = b.split()
    uc = ''
    for i in list_a:
        if i not in list_b:
            uc = uc+" "+i
    for j in list_b:
        if j not in list_a:
            uc = uc+" "+j
    return uc
# Driver code
a = "apple banana mango"
b = "banana fruits mango"

Also another way-using in-built function “symmetric_difference()”

def uncommon(a,b):
  return k
#Driver code
if __name__=="__main__":
  a="apple banana mango" 
  b="banana fruits mango"
['apple', 'fruits']

Another way to solve this problem

def uncommon(A, B):
    un_comm = [i for i in "".join(B).split() if i not in "".join(A).split()]
    return un_comm
#Driver code
A = "Geeks for Geeks" 
B = "Learning from Geeks for Geeks"
print(uncommon(A, B))
['Learning', 'from']

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