Skip to content

Courses
Tutorials
Practice
Contests

Python Tutorial
Interview Questions
Python Quiz
Python Glossary
Python Projects
Practice Python
Data Science With Python
Python Web Dev
DSA with Python
Python OOPs

Count frequencies of all elements in array in Python using collections module

Program to print all distinct elements of a given integer array in Python | Ordered Dictionary

Last Updated : 07 Apr, 2023

Comments

Improve

Suggest changes

Like Article

Like

Report

Given an integer array, print all distinct elements in array. The given array may contain duplicates and the output should print every element only once. The given array is not sorted. Examples:

Input: arr[] = {12, 10, 9, 45, 2, 10, 10, 45} Output: 12, 10, 9, 45, 2  Input: arr[] = {1, 2, 3, 4, 5} Output: 1, 2, 3, 4, 5  Input: arr[] = {1, 1, 1, 1, 1} Output: 1

This problem has existing solution please refer Print All Distinct Elements of a given integer array link. We will solve this problem in python quickly using Ordered Dictionary. Approach is simple,

Convert array into dictionary data structure using OrderedDict.fromkeys(iterable) function, it converts any iterable into dictionary having elements as Key in the same order they appeared in array.
Now iterate through complete dictionary and print keys.

Python3

   # Python program to print All Distinct
# Elements of a given integer array
 
from collections import OrderedDict
 
def printDistinct(input):
     # convert list into ordered dictionary
     ordDict = OrderedDict.fromkeys(input)
 
     # iterate through dictionary and get list of keys
     # list of keys will be resultant distinct elements 
     # in array
     result = [ key for (key, value) in ordDict.items() ]
 
     # concatenate list of elements with ', ' and print
     print (', '.join(map(str, result)))  
 
# Driver program
if __name__ == "__main__":
    input = [12, 10, 9, 45, 2, 10, 10, 45]
    printDistinct(input)
 
  

Output:

12, 10, 9, 45, 2

Approach#2:

The approach of this program is to use a set to keep track of the distinct elements while iterating through the input array. Whenever a new element is encountered, it is printed and added to the set. This ensures that only the distinct elements are printed.

Algorithm

Create a set to store distinct elements.
Traverse the array from start to end.
For each element, check if it is already present in the set.
If it is not present, then add it to the set and print the element.

Python3

   def distinct_elements(arr):
    distinct = set()
    for element in arr:
        if element not in distinct:
            print(element, end=' ')
            distinct.add(element)
 
arr = [12, 10, 9, 45, 2, 10, 10, 45]
distinct_elements(arr)
 
  

Output

12 10 9 45 2

Time Complexity: O(n), where n is the length of the input array.
Auxiliary Space: O(n), where n is the length of the input array in the worst case when all elements are distinct.

Count frequencies of all elements in array in Python using collections module

S

Shashank Mishra

Improve

Article Tags :

Python
Python dictionary-programs
python-dict

Practice Tags :

python
python-dict

Similar Reads

Program to print duplicates from a list of integers in Python

In this article, we will explore various methods to print duplicates from a list of integers in Python. The simplest way to do is by using a set. Using SetSet in Python only stores unique elements. So, we loop through the list and check if the current element already exist (duplicate) in the set, if

Count distinct elements in an array in Python

Given an unsorted array, count all distinct elements in it. Examples: Input : arr[] = {10, 20, 20, 10, 30, 10} Output : 3 Input : arr[] = {10, 20, 20, 10, 20} Output : 2 We have existing solution for this article. We can solve this problem in Python3 using Counter method. Approach#1: Using Set() Thi

Count frequencies of all elements in array in Python using collections module

Given an unsorted array of n integers which can contains n integers. Count frequency of all elements that are present in array. Examples: Input : arr[] = [1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 5] Output : 1 -> 4 2 -> 4 3 -> 2 4 -> 1 5 -> 2 This problem can be solved in many ways, refer

Different ways of sorting Dictionary by Keys and Reverse sorting by keys

Prerequisite: Dictionaries in Python A dictionary is a collection which is unordered, changeable and indexed. In Python, dictionaries are written with curly brackets, and they have keys and values. We can access the values of the dictionary using keys. In this article, we will discuss 10 different w

Python | Minimum number of subsets with distinct elements using Counter

You are given an array of n-element. You have to make subsets from the array such that no subset contain duplicate elements. Find out minimum number of subset possible. Examples: Input : arr[] = {1, 2, 3, 4} Output :1 Explanation : A single subset can contains all values and all values are distinct

Python | Count number of items in a dictionary value that is a list

In Python, dictionary is a collection which is unordered, changeable and indexed. Dictionaries are written with curly brackets, and they have keys and values. It is used to hash a particular key. A dictionary has multiple key:value pairs. There can be multiple pairs where value corresponding to a ke

Scraping And Finding Ordered Words In A Dictionary using Python

What are ordered words? An ordered word is a word in which the letters appear in alphabetic order. For example abbey & dirt . The rest of the words are unordered for example geeks The task at hand This task is taken from Rosetta Code and it is not as mundane as it sounds from the above descripti

Python - Find all elements count in list

In Python, counting the occurrences of all elements in a list is to determine how many times each unique element appears in the list. In this article, we will explore different methods to achieve this. The collections.Counter class is specifically designed for counting hashable objects. It provides

How to convert a dictionary into a NumPy array?

It's sometimes required to convert a dictionary in Python into a NumPy array and Python provides an efficient method to perform this operation. Converting a dictionary to NumPy array results in an array holding the key-value pairs in the dictionary. Python provides numpy.array() method to convert a

Program to print N minimum elements from list of integers

Our task is to extract the smallest N elements from a list of integers. For example, if we have a list [5, 3, 8, 1, 2] and want the smallest 3 elements, the output should be [1, 2, 3]. Weâ€™ll explore different methods to achieve this. Using heapq.nsmallestThis method uses the nsmallest() function fro

Corporate & Communications Address:

A-143, 7th Floor, Sovereign Corporate Tower, Sector- 136, Noida, Uttar Pradesh (201305)

Registered Address:

K 061, Tower K, Gulshan Vivante Apartment, Sector 137, Noida, Gautam Buddh Nagar, Uttar Pradesh, 201305

Advertise with us

Company
About Us
Legal
Privacy Policy
In Media
Contact Us
Advertise with us
GFG Corporate Solution
Placement Training Program

Languages
Python
Java
C++
PHP
GoLang
SQL
R Language
Android Tutorial
Tutorials Archive

DSA
Data Structures
Algorithms
DSA for Beginners
Basic DSA Problems
DSA Roadmap
Top 100 DSA Interview Problems
DSA Roadmap by Sandeep Jain
All Cheat Sheets

Data Science & ML
Data Science With Python
Data Science For Beginner
Machine Learning
ML Maths
Data Visualisation
Pandas
NumPy
NLP
Deep Learning

Web Technologies
HTML
CSS
JavaScript
TypeScript
ReactJS
NextJS
Bootstrap
Web Design

Python Tutorial
Python Programming Examples
Python Projects
Python Tkinter
Python Web Scraping
OpenCV Tutorial
Python Interview Question
Django

Computer Science
Operating Systems
Computer Network
Database Management System
Software Engineering
Digital Logic Design
Engineering Maths
Software Development
Software Testing

DevOps
Git
Linux
AWS
Docker
Kubernetes
Azure
GCP
DevOps Roadmap

System Design
High Level Design
Low Level Design
UML Diagrams
Interview Guide
Design Patterns
OOAD
System Design Bootcamp
Interview Questions

Inteview Preparation
Competitive Programming
Top DS or Algo for CP
Company-Wise Recruitment Process
Company-Wise Preparation
Aptitude Preparation
Puzzles

School Subjects
Mathematics
Physics
Chemistry
Biology
Social Science
English Grammar
Commerce
World GK

GeeksforGeeks Videos
DSA
Python
Java
C++
Web Development
Data Science
CS Subjects

@GeeksforGeeks, Sanchhaya Education Private Limited, All rights reserved

We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy

Improvement

Suggest Changes

Help us improve. Share your suggestions to enhance the article. Contribute your expertise and make a difference in the GeeksforGeeks portal.

geeksforgeeks-suggest-icon

Create Improvement

Enhance the article with your expertise. Contribute to the GeeksforGeeks community and help create better learning resources for all.

geeksforgeeks-improvement-icon

Suggest Changes

min 4 words, max Words Limit:1000

Thank You!

Your suggestions are valuable to us.

What kind of Experience do you want to share?

Interview Experiences

Admission Experiences

Career Journeys

Work Experiences

Campus Experiences

Competitive Exam Experiences