# Introduction to Sets in Python | HackerRank Solution

Hello coders, today we are going to solve Introduction to Sets in Python Hacker Rank Solution.

## Objective

A set is an unordered collection of elements without duplicate entries.

When printed, iterated or converted into a sequence, its elements will appear in an arbitrary order.

Example

```>>> print set()
set([])

>>> print set('HackerRank')
set(['a', 'c', 'e', 'H', 'k', 'n', 'r', 'R'])

>>> print set([1,2,1,2,3,4,5,6,0,9,12,22,3])
set([0, 1, 2, 3, 4, 5, 6, 9, 12, 22])

>>> print set((1,2,3,4,5,5))
set([1, 2, 3, 4, 5])

>>> print set(set(['H','a','c','k','e','r','r','a','n','k']))
set(['a', 'c', 'r', 'e', 'H', 'k', 'n'])

>>> print set({'Hacker' : 'DOSHI', 'Rank' : 616 })
set(['Hacker', 'Rank'])

>>> print set(enumerate(['H','a','c','k','e','r','r','a','n','k']))
set([(6, 'r'), (7, 'a'), (3, 'k'), (4, 'e'), (5, 'r'), (9, 'k'), (2, 'c'), (0, 'H'), (1, 'a'), (8, 'n')])```

Basically, sets are used for membership testing and eliminating duplicate entries.

Now, let’s use our knowledge of sets and help Mickey.

Ms. Gabriel Williams is a botany professor at District College. One day, she asked her student Mickey to compute the average of all the plants with distinct heights in her greenhouse.

Formula used:

Average = Sum of Distinct Heights / Total Number of Distinct Heights

## Input Format

The first line contains the integer, N, the total number of plants.

The second line contains the N space separated heights of the plants.

0 < N <= 100

## Output Format

Output the average height value on a single line.

Sample Input

```10
161 182 161 154 176 170 167 171 170 174```

Sample Output

`169.375`

Explanation

Here, set ([154, 161, 167, 170, 171, 174, 176, 182]) is the set containing the distinct heights. Using the sum() and len() functions, we can compute the average.

Average = 1355 / 8 = 169.375

## Solution – Introduction to Sets in Python – Hacker Rank Solution

### Python 3

```def average(array):