Python Program to find missing number in array

Interview Preparation

In this tutorial, you will learn writing a program using Python to find the missing number in integer array of 1 to 100. 

This Program is not generic, It has some limitations like 

  • It can find only one missing number in an array.
  • Here we are just adding numbers from 0 to n, where n is number of elements array can have.
  •  User can give input only between 0 to n.
  • To find missing number, subtract sum of numbers given by user from total sum of numbers from 0 to n.

Also Read This:  Java Program to find missing number in array. 

Python Program to find missing number in array

arr = []
n = int(input("enter size of array : "))
for x in range(n-1):
    x=int(input("enter element of array : "))
    arr.append(x)
sum = (n*(n+1))/2;
sumArr = 0
for i in range(n-1):
    sumArr = sumArr+arr[i];
print(int(sum-sumArr))

Output:

python missing number in array

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