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Learn how to create and use two-dimensional lists in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 8b - 2D Lists Creating a List with Multiple Dimensions Lists can be given another dimension to hold data that is related to each other . A scenario: Three students have taken two Chemistry tests, and their teacher has recorded the results in a 2-dimensional array (note that Python does not use arrays but uses lists instead): To create this in Python: Printing a 2D List To print the whole list, use a for loop to cycle through each record. I have altered the normal i variable to be 'record', so it is more descriptive: Use the index number to print a specific record . Look at the table above and remember that Python starts counting at 0 so Edward is record 0, Bella 1 and Jacob 2: To print a specific data value, you need to define the record number and then the data index . When using 2D lists, the first value is the row, and the second value is the column . Use the table at the very top to help you visualise this: Practice Task 1 Use the introduction at the top to help you create a 2D list with three friends in the first column, their age in the second column and their favourite colour in the third column. Print the whole list. Then print just the second person's information. Example solution: Searching Through a 2D List To search through a multi-dimensional list then you need to search through each record and then each data element for a specific value: Practice Task 2 Use the 2D list that you created in the first practice task. Ask the user to enter a name. Search through the list and print the record of that person's name. Example solution: ⬅ 8a - Using Lists 8 c - Dictionaries ➡

The list of topics in the 2020 Eduqas (part of WJEC) GCSE Computer Science specification. Eduqas GCSE Computer Science These pages are based on the Eduqas GCSE Computer Science 2020 specification . 1. Hardware 1.1 - The Central Processing Unit (CPU) 1.2 - The FDE Cycle 1.3 - Primary Storage 1.4 - Secondary Storage 1.5 - Performance 1.6 - Additional Hardware 2. Logical Operators & Boolean 2.1 - Logical Operators 2.2 - Boolean Algebra 3. Networks & Security 3.1 - Network Characteristics 3.2 - Data Packets & Switching 3.3 - Network Topology 3.4 - Network Hardware & Routing 3.5 - Protocols 3.6 - 7-Layer OSI Model 3.7 - The Internet 3.8 - Cyber Threats 3.9 - Protection Against Threats 4. Data 4.1 - Number Systems 4.2 - Signed Binary 4.3 - Binary Calculations 4.4 - Arithmetic Shift 4.5 - Character Sets & Data Types 4.6 - Graphical Representation 4.7 - Sound Representation 4.8 - Compression 5. Data Organisation 5.1 - Data Structures & File Design 6. Operating Systems 6.1 - Operating Systems 6.2 - Utility Software 7. Principles of Programming 7.1 - Language Levels 8. Algorithms & Constructs 8.1 - Programming Principles 8.2 - Understanding Algorithms 8.3 - Writing Algorithms 8.4 - Sorting & Searching Algorithms 8.5 - Validation & Verification 9. Software Development 9.1 - IDE Tools 10. Program Construction 10.1 - Translators 10.2 - Stages of Compilation 10.3 - Programming Errors 11. Technological Issues 11.1 - Impacts of Technology 11.2 - Legislation Component 2 (Programming Exam) Python

The first part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about comments and printing. Python - #1 - The Basics 1. Start with Commenting Programmers write A LOT of code. They need to understand exactly what they have written, especially if they are working as part of a team or returning to code after working on other projects. To help them understand what they have written, programmers use comments to annotate (explain) their code . Task 1 - Create a new Python program and use # to write a comment that says your name and the date. Save the file as 1-Basics.py In Python, type the # symbol then your message to write a comment. Comments are not printed when you run a program! It is a good idea to start every program with a comment, so you know what the program is about . 2. Printing to the Screen The most basic and common command you will use in Python is print . Inside the print brackets, you can write a message within speech marks . Your print command should turn purple - don't use any capital letters in Python unless it is inside speech marks! Task 2 - Write a nice message by using the print command, brackets and speech marks. Press F5 to run your program. 3. More Printing You can write multiple print lines one after another to print on different lines. Task 3 - Add two more print lines to your program. You can choose any message that you like. 4. New Lines You can use the special command \n to start a new line . This allows you to write on multiple lines but only use one print line. Use the backslash ( \ ) not the forward-slash ( / ). Task 4 - Use \n to write a 3 sentence conversation in only one line of code. Challenge Programs Use everything that you have learned on this page to help you create these programs... Challenge Task 1 - Days of the Week Create a new Python program. Save it as ' 1-Week.py ' Add a comment at the top with your name and the date. Create a program that prints the days of the week, with each day on a new line. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it should look like this: Challenge Task 2 - Conversation Create a new Python program. Save it as ' 1-Conversation.py ' Add a comment at the top with your name and the date. Create a program that prints a 6-line conversation between two people. It is up to you what these two people are talking about. BONUS : Try to use only one print line. BONUS : Have no empty spaces at the start of each line. When you run it, it could look something like this: #2 Variables >>>

Learn about how to perform binary addition and binary shifts. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 2.4b: Binary Addition & Shifts Exam Board: OCR Specification: J277 Watch on YouTube : Binary Addition Overflow Errors Binary Shifts Issues with Shifts Binary Addition Binary addition is a method of adding binary values without having to convert them into denary. How to add binary numbers: What is an overflow error? An overflow error occurs when a binary value is too large to be stored in the bits available . With a byte (8 bits ) the largest number that can be held is 255 . Therefore any sum of two binary numbers that is greater than 255 will result in an overflow error as it is too large to be held in 8 bits . What is binary shift? Binary shift is used to multiply and divide binary numbers . The effect of shifting left is to multiply a binary number. The effect is doubled by each place that is shifted . x The effect of shifting right is to divide a binary number. ÷ Shifting by 1 has an effect of 2 . Shifting by 2 has an effect of 4 . Shifting by 3 has an effect of 8 . For example, shifting left by 2 places has an effect of multiplying by 4 . Another example: Shifting right by 3 places has an effect of diving by 8 . How to shift a binary number: Binary Shifts Watch on YouTube Watch on YouTube Q uesto's Q uestions Binary Addition: 1. Explain what an overflow error is. [ 2 ] 2. Add together the following binary values. If an overflow error occurs you must state one has occurred. a. 010110012 and 010001012 [2 ] b. 110110112 and 010111012 [2 ] c. 001101102 and 011010112 [2 ] d. 110110112 and 010101112 [2 ] e. 011011012 and 110101102 [2 ] Binary Shifts: 1a. Draw a diagram to show the effect of multiplying and dividing a binary number . [2 ] 1b. Draw a diagram or table to show the effect a shift has for each place from 1 to 4 . For example, a shift of 1 place has an effect of 2. [4 ] 2. State the effect of the following shifts: a. Shift right by 2 places. b. Shift left by 1 place. c. Shift left 3 places. d. Shift right by 4 places. [ 1 each ] 3. Shift the following binary numbers and state the effect of the shift: a. 10101011 : Shift left by 2 places. b. 11101100 : Shift right by 3 places. c. 00001011 : Shift right by 2 places. d. 01101110 : Shift left by 1 place. [ 2 each ] 2.4a - Number Systems Theory Topics 2.4c - Character Storage

Test your ability to create a more complex program in Python based on a given scenario. Perfect for students learning GCSE Computer Science in UK schools. Extended Task 3 Hi, Susanna here, I want to make a blackjack-like program that I can play for fun at home in between revising for Computer Science. The aim of my blackjack game is to get as close to 21 as possible with the most number of cards, without going over. So... The user can choose whether to be hit with a new card (a number between 1 and 8) or fold and stop. Each number they are dealt adds up to their total . If the total goes over 21, then they lose . If they bust (when over 21) or folded then their final number and their number of cards is displayed . Blackjack For this task, you will need to create a document and include the following sections (with screenshots where appropriate): An introduction to explain the Purpose of your program . A List of Requirements for a successful program. Screenshots of your code (with comments in your code to show understanding). Testing – Create a plan to show how you will test your program and then explanations of any errors that you found and how they were fixed . An Evaluation of what worked, what didn’t, and how you met each of your requirements from your original list. Also, discuss further improvements that you could have made to improve your program. Example solution: Helpful reminders for this task: Think about the type of loop that you need. Will you need more than one loop? What variables will you need? Remember to use an input . What will you ask the user? How will you use their response? Remember to use ‘import random’ and randint to create a random number . What outputs do you need and when? What should you display… After each hand? At the beginning? At the end? ⬅ Extended Task 2 (Lottery) Extended Task 4 (Vet Surgery) ➡

Test your ability to create a more complex program in Python based on a given scenario. Perfect for students learning GCSE Computer Science in UK schools. Extended Task 2 Lottery 17 8 4 13 20 Create a program to simulate a lottery draw. First, create an appropriate print line to welcome the user to your lottery draw. Then let the user enter five numbers between 1 and 20. Next, randomise five numbers between 1 and 20. Check to see how many numbers match and output an appropriate response for each scenario (e.g. “You have not matched any numbers, better luck next time!”) Once you have made the base program implement subroutines and lists . Make it as efficient as possible and professional-looking. Use pauses to reveal each number one at a time like a real lottery draw to build suspense. For this task, you will need to create a document and include the following sections (with screenshots where appropriate): An introduction to explain the Purpose of your program . A List of Requirements for a successful program. Screenshots of your code (with comments in your code to show understanding). Testing – Create a plan to show how you will test your program and then explanations of any errors that you found and how they were fixed . An Evaluation of what worked, what didn’t, and how you met each of your requirements from your original list. Also, discuss further improvements that you could have made to improve your program. Example solution: Helpful reminders for this task: Inputting Numbers Random Numbers Logical Operators Subroutines ⬅ Extended Task 1 (Pork Pies) Extended Task 3 (Blackjack) ➡

Learn about different types of tools used in the data analysis process including data visualisation, data cleaning and GIS. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 3.5 - Data Analysis Tools Exam Board: OCR Specification: 2016 - Unit 2 The fifth stage of data analysis is to select the most appropriate tools to analyse the collected data. The method(s) selected will depend on the type of project and the established objectives. Data Tables Databases are often split into tables to be easier to update , view and manipulate . For example, a supermarket database may include a table of product information, another table of suppliers and another for actual stock levels. Separating the data into tables allows for simpler editing and also allows for the display of basic patterns . For example, looking at a table of stock levels in a supermarket can quickly show which products need to be ordered in as they are close to selling out. Data tables allow for the most simple form of pattern discovery and are a good method of speedy, short-term data analysis . However they present data in its current format and cannot show change or trends over time - a product may have a high stock level because it is popular and has just been ordered in, rather than because no-one is buying it. A simplified data table for a supermarket. Visualisation of Data Visualising data (by producing a chart or graph of collected data for example) makes it easier for an audience to see trends and patterns . Visualising data, like the bar chart to the right of the supermarket table from the tool above, makes it easier to understand and quicker to interpret . In this example, It is easier to see using the chart that steak pies are low in stock and should be re-ordered soon. A bar chart of the supermarket data table. Trend & Pattern Identification This tool links heavily to visualisation of data in allowing trends and patterns to be viewed as a visual format - such as producing a line graph of last year’s stock sales. Statistical analysis allows data analysts to examine numerical data and, if done correctly, can highlight relationships between different data elements - such as the price of a product and how many have been sold. Discovering links between variables is known as regression analysis . Data Cleaning Data cleaning ensures that any stored data is up-to-date and accurate , in accordance with the Data Protection Act ( 2018 ). Forms of data cleaning include removing customers who have not made a purchase in a certain amount of time (e.g. two years) and periodically checking that user addresses are up to date. Data cleaning would reduce the size of any data table by removing redundant, incorrect or unnecessary data . This would make it easier to work with the data table and would improve the data quality by removing erroneous and irrelevant data. GIS / Location Mapping Geographic Information Systems (GIS ) can be used to add geographic data to any analysis. For example, an organisation can track the geographical location of items or staff e.g. tracking the movement of shipping containers around the world to see production flow. This also works for courier services to see delays and delivery times in real-time . Q uesto's Q uestions 3.5 - Data Analysis Tools: 1. Describe how Fresh Food UK, from the question in 3.4 , could use each of the data analysis tools when trying to determine and present the most profitable stores across the country in the past year . a. Data Tables [3 ] b. Visualisation of Data [3 ] c. Trend & Pattern Identification [3 ] d. Data Cleaning [3 ] e. GIS / Location Mapping [3 ] 3.4 - Stages of Data Analysis Topic List 3.6 - Information Systems

Learn how to use mathematical operators in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 4b - Mathematical Operators Modulo Division The modulo operator - the percentage symbol % - will work out the remainder left over when one value is divided by another. print (30 % 6) = 0 30 ÷ 6 = 5, which is a whole number, so there is no remainder and 0 is output . print (30 % 7) = 2 30 ÷ 7 = 4 remainder 2 ; so the remainder is output . You can use modulo with variables too: num1 = 33 num2 = 4 print ( "The remainder is" , num1 % num2) The remainder is 1 = A common use of modulo is to check if a number is odd or even . If a number has no remainder when divided by 2 then it is even . = num = int ( input ( "Enter a number: " )) if num % 2 == 0: print (num, "is even." ) else : print (num , "is odd." ) Enter a number: 400 400 is even. Enter a number: 191 191 is odd. = Modulo Div i sion Task 1 ( Remainder) Ask the user to input a whole number . Use the modulo operator ( % ) to check if there is a remainder when the user's number is divided by 5 . Print the re mainder. Example solution: Enter a number: 123 The remainder when divided by 5 is 3 Modulo Div i sion Task 2 ( Rollercoaster) Use the odd/even program above to help solve this problem: A rollercoaster only lets people on in groups of 4 . Ask the user to input a number for how many people are in their group. Check if that number is directly divisible by 4 using modulo division ( % ). If it is then print “Perfect groups of four!” Else print “You will be split up” . Example solutions: Welcome to the Hyper Coaster! How many in your group? 6 You will be split up! Welcome to the Hyper Coaster! How many in your group? 12 Perfect groups of four! Integer Division Integer division removes any decimal numbers when performing division , leaving just the integer (whole number ). In Python integer division is performed using // . print (20 / 3) print (20 // 3) = 6.666666666666667 6 Integer Div i sion Task 1 ( Integer Division by 5 ) Use an input line with int to ask the user to enter a number . Use integer division ( // ) to divide the number by 5 without keeping any decimal values . Challenge: Improve your solution by altering the print line to be more user friendly . Example solutions: Enter a number: 27 5 Enter a number: 27 5 goes into 27 5 times. Integer Div i sion Task 2 ( Plane Rows) A large plane has 6 seats in each row. Input the number of passengers on the plane and use integer division to work out how many full rows will be filled. Example solution: How many passengers are there in total? 174 There will be 29 full rows on the plane. Exponent (Powers) An exponent is the number of times a value is multiplied by itself , for example 2 = 2 x 2 x 2 = 8 . The symbol to represent an exponent in Python is ** . For example: 4**2 represents 4 which is also 4 x 4 . 3 2 print (4**4) = 256 base = 5 exponent = 4 print (base**exponent) 625 = Exponent Task 1 ( Square Number) Use an input line with int to ask the user to enter a number . Output the square of this number. Example solution: Enter a number: 12 12 squared is 144 Exponent Task 2 ( Custom Exponent) Use an input line with int to ask the user to enter a number, this will be the base . Make another input line with int to ask for the exponent . Use ** between the base and the exponent and print it. Challenge: Make your solution better by including the base and exponent in the print line. Example solutions: Enter the base: 7 Enter the exponent: 3 343 Enter the base: 7 Enter the exponent: 3 7 to the power of 3 is 343 ⬅ 4a - If Statements 4 c - Log ical Operators ➡

Learn about the decomposition methods used in project planning such as abstraction, pattern recognition, modularisation (top down and bottom up) and parsing of requirements. Based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) (AAQ - Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 4.3 - Decomposition Methods Watch on YouTube : Abstraction Pattern Recognition Modularisation Parsing of Requirements Decomposition methods break complex problems or systems into smaller , more manageable parts . This makes development easier to plan , understand and implement . Decomposition also helps reduce errors and improve efficiency , as individual tasks can be more easily tested and debugged. For each of the four decomposition methods ( abstraction , pattern recognition , top-down and bottom-up modularisation and parsing requirements ) you need to know when each method is suitable to use , its advantages and disadvantages , how client requirements affect their selection and how they can be used to visualise application designs . Decomposition Methods Abstraction Abstraction is the process of simplifying a problem by ignoring irrelevant data and focusing only on the most important details . It is used in the early stages of design or planning , when managing complexity in large systems and when creating reusable components . Pattern Recognition Pattern recognition is used to identify similarities or trends in problems or client requirements . This allows for the reuse of existing components and aids in finding solutions for common issues . It is used during the planning or analysis phases and when dealing with similar tasks , inputs , outputs or processes . Modularisation Modularisation refers to the individual components that make up a larger project . In top-down modularisation , a larger system is broken down from a general overview into its most specific parts . The purpose of bottom-up modularisation is to build the system starting with the smaller , detailed components and combining them into larger subsystems . Parsing of Requirements To parse requirements means to systematically break down and analyse client requirements into actionable tasks or functions . It is used at the start of a project to ensure shared understanding between development teams and clients . Q uesto's Q uestions 4.3 - Decomposition Methods: 1. Explain the differences between top-down and bottom-up modularisation . [4 ] 2. Explain when abstraction would be an appropriate decomposition method to use. [3 ] 3. What are the advantages and disadvantages of parsing requirements ? [ 4 ] 4. Give one way each decomposition method can be used in software application development . [ 4 ] Alan Turing and his team used pattern recognition to analyse recurring sequences in encrypted German messages , helping to break the Enigma code , which was a major factor in the Allies’ victory in World War II . D id Y ou K now? 4.2 - Client Requirement Specs Topic List 5.1.1 - Human-Computer Interaction

Learn how to delay processes using the sleep command in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 5b - Sleep Using Sleep To pause a program, import sleep from the time library . Type the word sleep followed by the number of seconds that you wish the program to break for in brackets . It must be a whole number . Below is an example of a program that imports the sleep command and waits for 2 seconds between printing: from time import sleep print ( "Hello!" ) sleep(2) print ( "Goodbye!" ) You can implement the sleep command within a for loop to produce an effective timer that outputs each second waited to the screen: You could also use a variable instead of a fixed value with the sleep command such as below: from time import sleep for second in range (1,11): print (second) sleep(1) from time import sleep seconds = int ( input ( "How many seconds should I sleep? " )) print ( "Going to sleep..." ) sleep(seconds) print ( "Waking up!" ) Sleep Task ( Slow Calculator) Create a slow calculator program that needs time to think in between calculations. Print a message to greet the user , then wait 3 seconds and ask them to enter a number . Wait another 3 seconds and ask them to enter a second number . Wait 2 more seconds , print “Thinking…” then 2 seconds later print the total of the two numbers added together . Example solution: ⬅ 5a - Rando m 5c - Date & Time ➡

Learn about network forensics, penetration tests and methods of protection including anti-malware, firewalls, encryption and two-factor authentication. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.9: Protection Against Threats Exam Board: Eduqas Specification: 2020 Network Forensics & Penetration Testing What is network forensics? Network forensics is the monitoring of a network to identify unauthorised intrusions . Network forensics is used to record and analyse attacks on a network and to gather other information about how the network is performing. It is important for organisations to identify weaknesses in their networks so that they can fix them and be prepared for any type of attack or malware. Footprinting - Footprinting is one method of evaluating a network’s security . This is when a security team puts itself in the attacker’s shoes by obtaining all publicly available information about the organisation and its network . Footprinting allows the company to discover how much detail a potential attacker could find out about a system. The company can then limit the technical information about its systems that is publicly available . Penetration Tests Penetration tests are carried out as part of ethical hacking. Ethical hacking is when an organisation gives permission to specific 'good ' hackers to try and attack a system so that the weak points can be highlighted and then fixed. The purpose of a penetration test is to review the system's security to find any risks or weaknesses and to fix them . There are four main types of penetration tests : Internal tests are to see how much damage could be done by somebody within the company with a registered account. External tests are for white hat hackers to try and infiltrate a system from outside the company . Blind tests are done with no inside information , to simulate what a real attacker would have to do to infiltrate the system. + Targeted tests are conducted by the company's IT department and the penetration team cooperating together to find faults in the system. Anti-Malware & Firewalls Anti-Malware Software Anti-malware software is used to locate and delete malware, like viruses, on a computer system. The software scans each file on the computer and compares it against a database of known malware . Files with similar features to malware in the database are identified and deleted . There are thousands of known malware, but new forms are created each day by attackers, so anti-malware software must be regularly updated to keep systems secure. Other roles of anti-malware software: Checking all incoming and outgoing emails and their attachments . Checking files as they are downloaded . Scanning the hard drive for viruses and deleting them . Firewall A firewall manages incoming and outgoing network traffic . Each data packet is processed to check whether it should be given access to the network by examining the source and destination address . Unexpected data packets will be filtered out and not accepted to the network. Other roles of a firewall include: Blocking access to insecure / malicious web sites . Blocking certain programs from accessing the internet . Blocking unexpected / unauthorised downloads . Preventing specific users on a network accessing certain files . Other Methods of Protection Double Authentication Also known as two-factor authentication (2FA ), this is a method of confirming someone's identity by requiring two forms of authorisation , such as a password and a pin code sent to a mobile. 4392 Secure Passwords Usernames must be matched with a secure password to minimise the chances of unauthorised users accessing a system. Passwords should contain a mix of uppercase and lowercase letters , punctuation and numbers . Passwords should be of a substantial length (at least 8 characters) and should be regularly changed . ******** User Access Levels Access levels are used to only allow certain users to access and edit particular files. ' Read-Only ' access is when a user can only view a file and is not allowed to change any data . For example, a teacher might set homework instructions as read-only for students to view. ' Read and Write ' access allows a user to read and edit the data in a file. For example, a teacher might set an online workbook as read and write access for students to fill in. It is important to set access levels so that only authorised users can view and change data. The more users who have access to a file, the more likely it is to be compromised. Certain users may also have no access to a file - when they can't view or edit it. Encryption Encryption is the process of scrambling data into an unreadable format so that attackers cannot understand it if intercepted during transmission. The original data (known as plaintext ) is converted to scrambled ciphertext using an encryption key . Only at the correct destination will the encryption key be used to convert the ciphertext back into plaintext to be understood by the receiving computer. A very simple method of encryption is to use the XOR logical operator . XOR is used on the plaintext and key together to create the ciphertext . Using XOR again on the ciphertext and key will reverse the encryption to reveal the plaintext . Encryption using XOR Plaintext = 00110100 Key = 10100110 XOR Ciphertext = 10010010 Decryption using XOR Ciphertext = 10010010 / Key = 10100110 XOR Plaintext = 00110100 Q uesto's Q uestions 3.9 - Protection Against Threats: 1a. What is network forensics ? Why is it important ? [ 3 ] 1b. Explain what is meant by footprinting and why companies do it . [ 2 ] 2. What is an ethical hacker ? [2 ] 3a. Describe the purpose of penetration tests . [2 ] 3b. Describe each type of penetration test . [ 8 ] 4. Describe the purpose of anti-malware software and its different roles . [ 4 ] 5. Describe the purpose of a firewall and its different roles . [ 4 ] 6a. Describe double authentication . [2 ] 6b. State three rules for choosing a strong password . [ 3 ] 7. Describe the three types of access level . [6 ] 8a. Describe the purpose of encryption . [ 2 ] 8b. Explain how encryption works, using the terms plaintext , key and ciphertext . [ 4 ] 3.8 - Cyber Threats Theory Topics 4.1 - Number Systems

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