RGB Converter

Posted on February 17, 2017 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

Did you know that every colour on the screen can be represented using an RGB code (Red, Green, Blue) code. This code consists of three numbers between 0 and 255, indicating how much red, green and blue are used to recreate the colour. For instance the RGB code for:

Red is (255,0,0)
Green is (0,255,0)
Blue is (0,0,255)
Yellow is (255,255,0)
Orange is (255,165,0)

Graphic designer and software programmer sometimes prefer to use another notation based on hexadecimal RGB code where each of the three decimal values are converted into a two-digit hexadecimal code, resulting in a 6-digit (3×2) hexadecimal code. For instance:

Red is #FF000
Green is #00FF00
Blue is #0000FF
Yellow is #FFFF00
Orange is #FFA500

Check the following RGB Color picker to see how RGB codes work:

The aim of this challenge is to write a program to perform decimal RGB to hexadecimal colour codes conversion and vice-versa.

Your Code

Solution...

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Tagged with: Python

Binary Converter using Python

Posted on February 17, 2017 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

Did You Know?

Everything that is stored on a computer is stored as binary code. Binary code is made of bits (0 or 1). We often use Bytes to store data. A Byte is made of eight bits and can be used to store any whole number between 0 to 255. Check it yourself, click on the binary digits to create your own binary number:

128	64	32	16	8	4	2	1
1	1	1	1	1	1	1	1

128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255

Python Challenge

The purpose of this challenge is to write a Python script to convert a Binary number into denary and vice versa. To do so we will use the concept of binary left and right shifts as explained below.

Binary Left Shift

A binary left shift is used to multiply a binary number by two. It consists of shifting all the binary digit to the left by 1 digit and adding an extra digit at the end with a value of 0.

Binary Right Shift

A binary right shift is used to divide a binary number by two. It consists of shifting all the binary digit to the right by 1 digit and adding an extra digit at the beginning (to the left) with a value of 0.

Python Code

Solution...

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Tagged with: Binary, Python

BBC micro:bit – Hogwarts Sorting Hat

Posted on February 17, 2017 by Administrator Posted in BBC micro:bit, Block Programming, Computer Science, Physical Computing

In the Harry Potter series of novels written by British author J. K. Rowling, The Sorting Hat is a magical hat at Hogwarts that determines which of the four school Houses each new student belongs most to. These four Houses are Gryffindor, Hufflepuff, Ravenclaw, and Slytherin.

In this challenge we are going to write a program for the BBC micro:bit to act as the sorting hat. Whenever a students from Hogwarts school of Witchcraft and Wizardry will shake the BBC micro:bit, a message will appear telling them which house they belong in.

You will need to use the micro:bit website to create the code using the JavaScript Block Editor.

Block Programming

Here is the code to implement the Sorting Hat algorithm:

harry-potter-sorting-hat-BBC-microbit-javascript-code

Resetting the Sorting Hat

Add the following code to reset the Sorting Hat when either button A or button B is pressed:

Tagged with: BBC micro:bit, Selection

Password Checker

Posted on February 16, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

For this challenge we will write a program where the end-user has to type a password. The program will then return a score to tell the end-user how secure their password is based on the following criteria:

Criteria	Score
The password contains lowercase and uppercase characters.	+10 pts
The password contains numbers and letters.	+10 pts
The password contains at least one punctuation sign.	+5 pts
The password is at least 8 characters long.	+5 pts

Video Tutorial

Complete the code

We have started the code but have only implemented the first two criteria. Your task is to implement all 4 criteria.

Test Plan

Once your code is done, complete the following tests to check that your code is working as it should:

Test #	Input Values	Expected Output	Actual Output
#1	Password: mypassword	5 pts
#2	Password: myPassWord	15 pts
#3	Password: myPassWord123	25 pts
#4	Password: #myPa$$Word123	30 pts
#5	Password: ?gB;45#wq2	30 pts
#6	Password: (leave blank)	0 pts

Extension Task

How could you tweak your code to implement the following rules:

Criteria	Score
The password contains at least 2 lowercase and at least 2 uppercase characters.	+15 pts
The password contains at least 2 numbers:	+15 pts

Solution...

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Tagged with: String Manipulation

Happy Birthday!

Posted on February 16, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

For this challenge we are going to write a Python program which will ask the end-user to enter their date of birth in the following format: dd/mm/yyyy.

The program will then calculate and display the following information:

The age of the user,
The number of days the user has lived for,
The week day (Monday to Sunday) corresponding to their Date of Birth,
The number of days left until the user’s next birthday,
A “Happy Birthday” message if today is the user’s birthday!

Learning Objectives

By completing this challenge you are learning various techniques to manipulate and format dates. These include formating a date in the dd/mm/yyyy format, retireving today’s date or calculating the difference in days or years between two dates.

Solution

Solution...

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Tagged with: Date and Time, Python Challenge

Days Until Summer

Posted on February 16, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Did you know?

Summer starts on the Summer Solstice which, in the Northern hemisphere, is the 21^st of June. It ends three months later, on September the 22^nd, a date known as known as Autumnal equinox, when the Autumn season starts.

For this challenge you will write a Python script that retrieves today’s date to find out if we are in Summer or not. If not, it will calculate the number of days until next Summer, which could be in the same calendar year or in the following calendar year (in case we have already passed this year Summer season).

To do so we will reuse and adapt the following code used to calculate the number of days until next Christmas. Your task is to analyse how this code works to then make the necessary amendments to:

Find out if we are already in the Summer season,
if, not find out if this year Summer is already past,

if it has, calculate the number of days left till next year Summer,
otherwise, calculate the number of days till this year Summer.

Python Code

Solution...

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Tagged with: Date & Time

Which Season?

Posted on February 15, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Did you know?:

Though we all agree that a calendar year is divided into four seasons, people sometimes disagree on the dates when these seasons start or finish. Many bodies, for example meteorologists, adopt a convention for the purpose of presenting statistics by grouping the twelve months of the year into four three-month seasons, for example March, April and May being taken as Spring.

In this case the seasons could be defined as follows:

From	To	Season
1^st September	30^th November	Autumn
1^st December	28/29^th February	Winter
1^st March	31^st May	Spring
1^st June	31^th August	Summer

Other scientists and astronomers prefer to define the four seasons based on astronomical events known as the equinoxes and the solstices. The equinoxes occur in March and September when the Sun is ‘edgewise’ to the Earth’s axis of rotation so that everywhere on Earth has twelve hours of daylight and twelve hours of darkness. The solstices occur in June and December when the Earth’s axis is at its extreme tilt towards and away from the Sun so at mid-day it appears at its highest in one hemisphere and at its lowest in the other.

The exact dates for the solstices and equinoxes vary from one year to the other but are around the 21st of the months mentioned above.

From	To	Season
21^st September	20^th December	Autumn
21^st December	20^th March	Winter
21^st March	20^th June	Spring
21^st June	20^th September	Summer

Your Challenge:

Write a computer program that retrieves today’s date. The program should then display the season for this date based on the astronomical definition of the four seasons.

We have started the code for you but have only worked out the dates for Spring. You can now complete the code to cater for all four seasons.

Solution...

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Tagged with: Date & Time, Python, Selection

Love Match Calculator

Posted on February 14, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

For this challenge we will write a program that will prompt the user to enter two first names. The program will then calculate and return a Love Match Score based on the following criteria:

Criteria	Score
Both first names have the same numbers of letters.	+20 pts
Both first names start with a vowel.	+10 pts
Both first names start with a consonant.	+10 pts
Both first names have the same number of vowels.	+12 pts
Both first names have the same number of consonants.	+12 pts
Both first names contain at least a “l”, “o”, “v” or “e”.	+7 pts

Complete the code

We have started the code but have only implemented the first two criteria. Your task is to implement all 6 criteria.

Test Plan

Once your code is done, complete the following tests to check that your code is working as it should:

Test #	Input Values	Expected Output	Actual Output
#1	Firstname #1: Luna Firstname #2: Evan	51 pts
#2	Firstname #1: Alice Firstname #2: Nolan	27 pts
#3	Firstname #1: Maya Firstname #2: Leo	22 pts
#4	Firstname #1: Nora Firstname #2: Lillian	17 pts
#5	Firstname #1: Ivy Firstname #2: Eli	61 pts
#6	Firstname #1: Sofia Firstname #2: Logan	37 pts

Solution...

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Tagged with: Python, String Manipulation

Lossless Compression

Posted on February 6, 2017 by Administrator Posted in A Level Concepts, Computer Science, Computing Concepts, GCSE Concepts

The purpose of lossless compression is to reduce the amount of storage space needed to save some information, without losing any information hence without losing quality.

Lossless compression can be used to store text-based information in a more effective way.

Look at the above text file used to store the pattern of a lego tower. Can you think of a better way to store this information?

Method #1: Run-length Encoding

Run-length encoding (RLE) is a very simple form of lossless data compression in which runs of data (that is, sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count.

Apply run-length encoding to the lego tower:

Method #2: Dictionary Coding

Dictionary coding, aka substitution coding, is a lossless data compression approach which consists of searching for matches between the text to be compressed and a set of strings contained in a data structure (called the ‘dictionary’) maintained by the encoder. When the encoder finds such a match, it substitutes a reference to the string’s position in the data structure.

For instance in we could use the following dictionary:

B -> Blue
G -> Green
R -> Red
Y -> Yellow

Apply dictionary codeing to the lego tower:

Combining Both Techniques:

We can combine both Dictionary Coding and Run-Length Encoding to compress out file even further:

Apply both techniques to your lego tower:

Lossless compression of bitmap pictures

We have applied lossless compression to a text file. How could we use this type of compression for picture files?

Domain Name Server

Posted on February 3, 2017 by Administrator Posted in A Level Concepts, Computer Science, GCSE Concepts, Python - Intermediate, Python Challenges, Solved Challenges

Domain Name Servers (DNS) are the Internet’s equivalent of a phone book. They maintain a directory of domain names and translate them to numerical IP addresses. These IP addresses are used to identify and locate the web-servers on the Internet network.

Domain names such 101computing.net are easy for people to remember. Computers however access websites based on IP addresses, hence the needs for domain name servers: when typing a website address in your web browser such as http://www.101computing.net, your request will reach a domain name server that will convert the domain name part of the address (101computing.net) into its matching IP address.

Your Challenge

For this challenge we are going to create a Python script to “act as a domain name server”. The script will ask the user to enter a domain name, search for this domain name within its own directory of domain names using a linear search and if found, return the matching IP address.

Our DNS script will use a text file with a short list of just 32 domain names and IP addresses. This data is organised as follows:

Domain Name,IP Address

You can download this text file:

dns.csv

You can find out more about how to access text files in Python by reading this blog post.

Method 1: Linear Search

To find the requested domain name you will first implement a linear search: your algorithm will need to read the dns.csv file one line at a time and check if the domain name is a match.

Below is the flowchart of a linear search:

Method 2: Binary Search

You may have noticed that the list of domain names in the dns.csv file is sorted in alphabetical order. This is a key requirement to implement a binary search, a more efficient approach to search through a sorted set of data.

Below is the flowchart of a binary search:

Did you know?

Currently most IP addresses are using the IPv4 format, based on 4 numbers between 0 and 255 sepearated by a dot.

The IPv4 protocol however will soon be upgraded to the IP version 6 (IPv6) internet protocol. The reason for this upgrade is that there is need to generate more IP addresses to allow more devices (webservers, desktops, laptops, smartphones, smartwatches and other connected objects) to have a unique IP address on the network. An IPv6 address is based on 128 bits (instead of 32 bits for an IPv4 address).

Solution...

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Tagged with: Binary Search, File Handling, Flowchart, Linear Search, Python

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Your Code

Solution...

Did You Know?

Python Challenge

Binary Left Shift

Binary Right Shift

Python Code

Solution...

Block Programming

Resetting the Sorting Hat

Video Tutorial

Complete the code

Test Plan

Extension Task

Solution...

Learning Objectives

Solution

Solution...

Did you know?

Python Code

Solution...

Did you know?:

Your Challenge:

Solution...

Complete the code

Test Plan

Solution...

Method #1: Run-length Encoding

Method #2: Dictionary Coding

Combining Both Techniques:

Lossless compression of bitmap pictures

Your Challenge

Method 1: Linear Search

Method 2: Binary Search

Did you know?

Solution...

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