Tally Marks Counter

Posted on March 1, 2017 by Administrator Posted in Computer Science, Python - Beginner, Python Challenges, Solved Challenges

Tally marks are a form of numeral system used for counting. They are most useful in counting or tallying ongoing results, such as the score in a game or sport, as no intermediate results need to be erased or discarded.

For this challenge you will write a Python script that:

Asks the user to enter a number,
Converts the user input to an integer,
Translates this number into tally marks,
Displays the tally marks on screen.

Note that, as we will be using a text-based output, we will use the following text to represent the tally marks:

1	2	3	4	5	6	7	…
\|	\|\|	\|\|\|	\|\|\|\|	\|\|\|\|-	\|\|\|\|- \|	\|\|\|\|- \|\|	…

DIV & MOD

In Python, the // operator and the % operator can be used to calculate the quotient (a.k.a. DIV) and the remainder (a.k.a. MOD) of a division. For instance:

Quotient: 14 DIV 5 = 14 // 5 = 2
Remainder: 14 MOD 5 = 14 % 5 = 4

In other words: 14 = 5 * 2 + 4

We will use these operators to find out how many blocks of 5 tallies we need to print and how many tallies are remaining.

Tally Marks Counter – Solved

Your Task

Use a similar approach to:

Ask the user to type a number of hours and convert this into days and hours knowing that there are 24 hours in a day. So for instance: 54 hours should be displayed as 2 days and 6 hours.

Ask the user to type a number of days and convert this into years and days assuming that there are 365 days in a year. So for instance: 892 days should be displayed as 2 years and 162 days.

Ask the user to type a number of seconds and convert this into hours, minutes and seconds knowing that there are 60 minutes in an hour and 60 seconds in a minute. So for instance: 8500 seconds should be displayed as 2 hours and 21 minutes and 40 seconds.

Solution...

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Hangman Game

Posted on February 27, 2017 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

For this challenge, you are going to create a game of hangman. The computer will pick a word randomly within a given list of words. The player will have to guess the word by suggesting one letter at a time and the computer will automatically check if the letter given is included in the word to guess. If not it will add one element to the hanged stick man drawing.

Complete the Code

We have started the code for you, but you will need to complete this code:

Step 1: Display the word replacing “_” with letters that have been guessed correctly. You can use the following flowchart to help you with this step:

Step 2: Display the hangman based on the number of lives remaining.
Step 3: Use a loop to repeat the above steps. The game should stop when the user guessed the words or when they have lost all their lives.

Solution...

The solution for this challenge is available to full members!
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Tagged with: String Manipulation

Bowling Scoreboard

Posted on February 27, 2017 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

The aim of this challenge is to create a scoreboard for a game of ten-pin bowling. It will be used to automatically calculate the total score of a player as they progress through the ten rounds of the game.

The scoring system in a game of ten-pin bowling is fairly complex to understand. Check the link provided below to fully understand the scoring system before attempting to complete this challenge:

Ten-pin Bowling – Scoring System:
https://en.wikipedia.org/wiki/Ten-pin_bowling#Scoring

World Bowling Scoring

The World Bowling scoring system—described as “current frame scoring”—awards points as follows:

strike: 30 (regardless of ensuing rolls’ results)
spare: 10 plus pinfall on first roll of the current frame
open: total pinfall for current frame

The maximum score is 300.

World Bowling scoring is an easier scoring system as the traditional scoring system described below. It is thought to make bowling easier to follow than with traditional scoring, increase television viewership, and help bowling to become an Olympic sport.

Traditional Scoring

In general, one point is scored for each pin that is knocked over. So if a player bowls over three pins with the first shot, then six with the second, the player would receive a total of nine points for that frame. If a player knocks down nine pins with the first shot, but misses with the second, the player would also score nine. When a player fails to knock down all ten pins after their second ball it is known as an open frame.

In the event that all ten pins are knocked over by a player in a single frame, bonuses are awarded.

A ten-pin bowling scoresheet showing how a strike is scored

Strike: When all ten pins are knocked down with the first ball (called a strike and typically rendered as an “X” on a scoresheet), a player is award ten points, plus a bonus of whatever is scored with the next two balls. In this way, the points scored for the two balls after the strike are counted twice.

Frame 1, ball 1: 10 pins (strike)

Frame 2, ball 1: 3 pins

Frame 2, ball 2: 6 pins

The total score from these throws is:

Frame one: 10 + (3 + 6) = 19
Frame two: 3 + 6 = 9

TOTAL = 28

Two consecutive strikes are referred to as a “bakfast”. Some locations still call it a “Hambone” even though that term has been changed to mean 4 strikes in a row by announcers on television. (Four strikes in a row is also referred to as a “Llama.”)

A double’s pinfall is:

Frame 1, ball 1: 10 pins (Strike)

Frame 2, ball 1: 10 pins (Strike)

Frame 3, ball 1: 9 pins

Frame 3, ball 2: 0 pins (recorded as a dash ‘-‘ or ‘0’ on the scoresheet)

The total score from these throws is:

Frame one: 10 + (10 + 9) = 29

Frame two: 10 + (9 + 0) = 19

Frame three: 9 + 0 = 9

TOTAL = 57

Three strikes bowled consecutively are known as a “turkey” or “triple”.

A turkey’s pinfall is:

Frame 1, ball 1: 10 pins (Strike)

Frame 2, ball 1: 10 pins (Strike)

Frame 3, ball 1: 10 pins (Strike)

Frame 4, ball 1: 0 pins (Gutterball)

Frame 4, ball 2: 9 pins

The total score from these throws is:

Frame one: 10 + (10 + 10) = 30

Frame two: 10 + (10 + 0) = 20

Frame three: 10 + (0 + 9) = 19

Frame four: 0 + 9 = 9

TOTAL = 78

Longer strings of strikes are called by various names, including “-Bagger” (Four Bagger), “Llama” (Four consecutive), and “-Pack” (Six Pack) depending on local use, equipment, and exposure to the sport. Recently, the event of bowling four consecutive strikes has also been called a “hambone”.Six strikes and nine strikes in a row can also be referred to “Wild Turkeys” and “Golden Turkeys” respectively. Any string of strikes starting in the first frame or ending “off the sheet” (where all of a bowler’s shots from a certain frame to the end of the game strike) are often referred to as the “front” or “back” strikes, respectively (e.g., the “front nine” for strikes in frames 1–9, or the “back six” for strikes in frames 7, 8, and 9 with a turkey in the tenth). A “perfect game” or 12 strikes in a row is also rarely referred to as the “Thanksgiving Turkey”. A “Clean Game” is a game with strikes or spares in every frame (not counting bonus balls).

A small number of bowling fans have recognized that naming each strike in a consistent manner adds to the enjoyment and excitement of the game. Based on this, a growing number of bowlers subscribe to the “Duck, Duck, Turkey” method of titling consecutive strikes. In keeping with the tradition that the third consecutive strike is called a “Turkey,” every third strike references turkeys and all strikes under this method have been named after birds as follows: Strike 1 – Duck; Strike 2 – Duck; Strike 3 – Turkey; Strike 4 – Goose; Strike 5 – Chicken; Strike 6 – Turducken; Strike 7 – Penguin; Strike 8 – Flamingo; Strike 9 – Turkey Vulture; Strike 10 – Woodpecker; Strike 11 – Eagle; Strike 12 – Turkey Hawk.

A player who scores multiple strikes in succession would score like so:

Frame 1, ball 1: 10 pins (strike)

Frame 2, ball 1: 10 pins (strike)

Frame 3, ball 1: 4 pins

Frame 3, ball 2: 2 pins

The score from these throws are:

Frame one: 10 + (10 + 4) = 24
Frame two: 10 + (4 + 2) = 16
Frame three: 4 + 2 = 6

TOTAL = 46

The most points that can be scored in a single frame is 30 points (10 for the original strike, plus strikes in the two subsequent frames).

A player who bowls a strike in the tenth (final) frame is awarded two extra balls so as to allow the awarding of bonus points. If both these balls also result in strikes, a total of 30 points (10 + 10 + 10) is awarded for the frame. Some people call it “striking out”, since three strikes in baseball equals an out.

A ten-pin bowling scoresheet showing how a spare is scored

Spare: A “spare” is awarded when no pins are left standing after the second ball of a frame; i.e., a player uses both balls of a frame to clear all ten pins. A player achieving a spare is awarded ten points, plus a bonus of whatever is scored with the next ball (only the first ball is counted). It is typically rendered as a slash on scoresheets in place of the second pin count for a frame.

Example:

Frame 1, ball 1: 7 pins

Frame 1, ball 2: 3 pins (spare)

Frame 2, ball 1: 4 pins

Frame 2, ball 2: 2 pins

The total score from these throws is:

Frame one: 7 + 3 + 4 (bonus) = 14
Frame two: 4 + 2 = 6

TOTAL = 20

A player who bowls a spare in the tenth (final) frame is awarded one extra ball to allow for the bonus points.

Solution...

The solution for this challenge is available to full members!
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Tagged with: Scoring System

Guess the Number: Binary Search

Posted on February 27, 2017 by Administrator Posted in Algorithms, Algorithms (GCSE), Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Before attempting this challenge, make sure you have completed our previous Guess the Number challenge first where the player plays against the computer.

In this version, the player will be asked to enter a number between 1 and 100. The computer will then use a binary search algorithm to try to guess the correct number keeping the number of guesses to a minimum.

The binary search is a very effective algorithm to search through a large list that is already sorted, in our case the list of numbers from 1 to 100. It is based on the following flowchart:

Complete the Code

Solution...

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Tagged with: Binary Search

Roman Numerals Conversion

Posted on February 27, 2017 by Administrator Posted in Computer Science, Python - Advanced, Python Challenges, Solved Challenges

For this challenge, your aim is to write a program used to convert whole numbers (integer) into roman numerals and vice versa.

Roman Numerals are based on seven symbols:

Symbol	Value
I	1
V	5
X	10
L	50
C	100
D	500
M	1,000

Complete the code

Test Plan

Test #	Input Values	Expected Output	Actual Output
#1	8	VIII
#2	75	LXXV
#3	2017	MMXVII
#4	CI	101
#5	MMXVII	2017
#6	MCMXLV	1945

Solution...

The solution for this challenge is available to full members!
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Tagged with: String Manipulation

Leaderboard

Posted on February 24, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Before completing this challenge you will need to make sure you have already completed a game or a quiz in Python with a scoring system.

You will then add a leaderboard functionality to your existing game or quiz in order to:

Store the player score at the end of the game,
Add an option for the player to view the leaderboard showing the ten highest scores sorted in descending order.

For this challenge you will create a leaderboard using a text file. The leaderboard.txt file will use the following format:

player_name;score;

You can download this example file:

leaderboard.txt

In order to complete this challenge you can read more about file handling techniques using Python, including how to append data at the end of a text file and how to read and extract data from a text file.

Storing New Scores

Our first step, is to store a new leaderboard entry at the end of the text file. This could would be needed once the player has completed the game/quiz.

The following code would be used to append the username and the score at the end of the leaderboard.txt file.

import random
username = input("Enter username:")
score = random.randint(0,2000) #Here we don't have a game or a quiz, so let's generate a random score instead.

file = open("leaderboard.txt","a")  
file.write(username + ";"+str(score)+";"+"\n")  
file.close()

Reading, Sorting and Displaying the Leaderboard

Before displaying the leaderboard on screen, we need to sort it in descending order of scores (highest to lowest). To do so we will first extract all the entries from the leaderboard.txt file and store these into a list using the following code:

file = open("leaderboard.txt","r")  
#Prepare the list (empty list to start with)  
scores = []  
  
#Read through the text file line by line  
for eachLine in file:  
   #Extract the data from the text file  
   splitData=eachLine.split(";")  
   if len(splitData)==3:  
      username = splitData[0]  
      userscore = int(splitData[1])  
      #Append this data to the list of scores  
      scores.append([username,userscore])  
  
file.close()

Now that we have loaded all the entries from the leaderboard.txt file into a list called scores, we can sort this list in descending order of scores, using the following code:

#Sort the list of scores in DESCENDING order  
sortedScores = sorted(scores,key=lambda sort: sort[1], reverse=True)

To only keep the top 10 scores we will slice the sorted list to the top 10 scores.

#only keep the top 10 scores:  
del sortedScores[10:]

The final step is to display these 10 top scores on screen:

#Output top 10 scores  
for score in sortedScores:  
   print(score[0] + ": " + str(score[1]))

Python Code

Let’s test this code. To make our program easier to read we have used the code provided below to create our own functions storeScore() to append a new score to the leaderboard file and displayLeaderboard() to extract data from the learberoard.txt file, sort all entries in descending order of score, and display the top 10 scores.

Solution...

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Tagged with: CSV, File Handling

Boarding Pass Validation

Posted on February 24, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

Scenario

You are writing a computer program for an airline company. The program will be used at a check-in desk to generate and print custom boarding passes.

The program captures several user inputs before generating the pass.

In order to make your program more robust, you decide to implement validation routines so that any invalid input is detected and automatically rejected by the program.

Your task is to complete the code below to implement the following validation checks:

The firstname and lastname of the passenger cannot be left blank,
The airport codes (departure and arrival) have to be exactly 3 characters long,
The airport codes (departure and arrival) should be automatically converted to UPPERCASE,
The program should ask whether or not a QR code will be printed on the boarding pass. Only a “Yes” or a “No” answer should be accepted,
The gate number has to be based on the following format: 1 uppercase letter + 2-digit number,
The flight number has to be based on the following format: 2 uppercase letters + 4-digit number,
The departure and arrival times must be in the 12:60 AM/PM format,
The date must be in the DD/MM/YYYY format.

Validation Techniques

String CasePresence CheckInteger OnlyRange CheckLookup CheckCharacter CheckLength CheckTry again!

In Python you can change the case of a sting using .lower(), .upper() and .title() method.

e.g. To retrieve a username in lower case:

username = input("Enter your username:").lower()

e.g. To retrieve a last name in title case:

lastname = input("Enter your last name:").title()

e.g. To retrieve a postcode in upper case:

postcode = input("Enter your postcode:").upper()

You can also remove all leading and tailing space from a user input you can use the .strip() method.

name = input("Enter your name:").strip()

Input Validation: Presence Check

name = input("Enter your name:").strip() 

if name=="":
    print("Empty name!")
else:
    print("Thank you!")

Input Validation: Type Check – Integer?

number = input("Type a number:")

if number.isdigit():
    print("This is a number")
else:
    print("This is not a whole number")

Input Validation: Range Check

number = int(input("Type a number between 1 and 5:"))

if number>=1 and number<=5:
    print("Valid number")
else:
    print("Invalid number")

Input Validation: Lookup Check

drive = input("Can you drive?").lower()

if drive in ["yes","no"]:
    print("Valid answer")
else:
    print("Invalid answer")

Input Validation: Character Check

email = input("Type your e-mail address:")

if "@" in email:
    print("Valid e-mail address")
else:
    print("Invalid e-mail address")

postcode = input("Type your postocode:").upper()

if postcode[0] in "ABCDEFGHIJKLMNOPQRSTUVWXYZ" and postcode[1] in "ABCDEFGHIJKLMNOPQRSTUVWXYZ" and postcode[2] in "123456789":
    print("Valid postcode")
else:
    print("Invalid postcode")

Input Validation: Length Check

password = input("Type a password:")

if len(password)>=8:
    print("Valid password")
else:
    print("Invalid password")

Try Again! Using a While Loop:

name = input("Enter your name:")

while name=="":
    print("You must enter your name! Please try again!")
    name = input("Enter your name:")

print("Welcome " +  name)

You can investigate more advance approaches to implement validation subroutines on this blog post.

Complete the code

Solution...

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Tagged with: Validation

Arithmetic Quiz

Posted on February 22, 2017 by Administrator Posted in Computer Science, Python - Intermediate, Python Challenges, Solved Challenges

For this challenge we will create a maths quiz consisting of ten arithmetic questions. Each question will be randomly generated using two random operands between 1 and 12 and one random operator, either + (addition), – (subtraction) or x (multiplication). We will not include the division operator as this could result in a decimal value.

We will include a scoring system to our quiz. The player will be asked one question at a time and score 10 points per correct answer and lose 5 points per incorrect answer.

Complete the code

We have started with just a few lines to generate a random question.
Your task is to add some code to:

Calculate the correct answer,
Compare the user answer with the correct answer to see if the user is correct or not,
Add 10 points for a correct answer or subtract 5 points for an incorrect answer,
Use a loop to repeat this code 10 times,
Display the final score, out of 100.

Extension Task

Why not add a leaderboard to your quiz. This would be used to store the player’s scores and display the top ten scores on screen, in descending order.

Solution...

The solution for this challenge is available to full members!
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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...

The solution for this challenge is available to full members!
Find out how to become a member:
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Tagged with: Binary, Python

1	2	3	4	5	6	7	…
\|	\|\|	\|\|\|	\|\|\|\|	\|\|\|\|-	\|\|\|\|- \|	\|\|\|\|- \|\|	…

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DIV & MOD

Tally Marks Counter – Solved

Your Task

Solution...

Complete the Code

Solution...

World Bowling Scoring

Traditional Scoring

Solution...

Complete the Code

Solution...

Complete the code

Test Plan

Solution...

Storing New Scores

Reading, Sorting and Displaying the Leaderboard

Python Code

Solution...

Scenario

Validation Techniques

Input Validation: Presence Check

Input Validation: Type Check – Integer?

Input Validation: Range Check

Input Validation: Lookup Check

Input Validation: Character Check

Input Validation: Length Check

Try Again! Using a While Loop:

Complete the code

Solution...

Complete the code

Extension Task

Solution...

Your Code

Solution...

Did You Know?

Python Challenge

Binary Left Shift

Binary Right Shift

Python Code

Solution...

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