w3resource

Python Challenges: Find the single number in a list that doesn't occur twice

Python Challenges - 1: Exercise-12 with Solution

Write a Python program to find the single number in a list that doesn't occur twice.

Explanation:

Python: single number in a list that doesn't occur twice

Sample Solution:

Python Code:

def single_number(arr):
    result = 0
    for i in arr:
        result ^= i
    return result

arr1 = [5, 3, 4, 3, 4]
arr2 = [3, 2, 5, 2, 1, 5, 3]

print(single_number(arr1))
print(single_number(arr2))

Sample Output:

5                                                                                                             
1

Flowchart:

Python Flowchart: Find the single number in a list that doesn't occur twice

Python Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a Python program to compute and return the square root of a given 'integer'.
Next: Write a Python program to find the single element in a list where every element appears three times except for one.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Follow us on Facebook and Twitter for latest update.