Python: Find the missing number in a given array of numbers between 10 and 20

Last update on March 28 2025 12:51:20 (UTC/GMT +8 hours)

24. Find Missing Number in an Array of Numbers Between 10 and 20

Write a Python program to find the missing number in a given array of numbers between 10 and 20.

Sample Solution-1:

Python Code:

import array as arr
def test(nums):
    return sum(range(10, 21)) - sum(list(nums))

array_num = arr.array('i', [10, 11, 12, 13, 14, 16, 17, 18, 19, 20])
print("Original array:")
for i in range(len(array_num)):    
    print(array_num[i], end=' ')
print("\nMissing number in the said array (10-20): ",test(array_num))
 
array_num = arr.array('i', [10, 11, 12, 13, 14, 15, 16, 17, 18, 19])
print("\nOriginal array:")
for i in range(len(array_num)):    
    print(array_num[i], end=' ')
print("\nMissing number in the said array (10-20): ",test(array_num))

Sample Output:

Original array:
10 11 12 13 14 16 17 18 19 20 
Missing number in the said array (10-20):  15

Original array:
10 11 12 13 14 15 16 17 18 19 
Missing number in the said array (10-20):  20

Flowchart:

Sample Solution-2:

Python Code:

import array as arr
def test(nums):
    return 165 - sum(list(nums))

array_num = arr.array('i', [10, 11, 12, 13, 14, 16, 17, 18, 19, 20])
print("Original array:")
for i in range(len(array_num)):    
    print(array_num[i], end=' ')
print("\nMissing number in the said array (10-20): ",test(array_num))
 
array_num = arr.array('i', [10, 11, 12, 13, 14, 15, 16, 17, 18, 19])
print("\nOriginal array:")
for i in range(len(array_num)):    
    print(array_num[i], end=' ')
print("\nMissing number in the said array (10-20): ",test(array_num))

Sample Output:

Original array:
10 11 12 13 14 16 17 18 19 20 
Missing number in the said array (10-20):  15

Original array:
10 11 12 13 14 15 16 17 18 19 
Missing number in the said array (10-20):  20

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to identify the missing number in a sorted array by computing the difference between the expected sum and the actual sum.
Write a Python program to use set operations to find the missing number in an array representing a continuous range.
Write a Python program to iterate over a range from 10 to 20 and return the number that is not present in the array.
Write a Python program to implement a function that takes an array and returns the missing element in a consecutive range, or a default value if none is missing.

Python Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a Python program to remove all duplicate elements from a given array and returns a new array.
Next: Python Conditional Statements and Loops Exercises Home.