Informatics Practices lessons

23 lessons

• Business Information Practice: Turn Data into a Decision – Business information practice means using data to help run a business. Data are raw facts and numbers, such as the cups sold each day. Information is data that has been put in order and worked on so that it helps you decide. The practice has five steps: collect data, organise it in a table or spreadsheet, calculate (total, average, biggest and smallest), show it in a chart, and decide. In the juice-stall project, mango sells 12, 18, 15, 20 and 25 cups from Monday to Friday. The total is 90, the average is 18 and the best day is 25. Lemon sells 10, 9, 11, 8 and 12, with an average of 10. The chart shows mango growing, so the owner decides to make more mango. Good information needs correct data, and business data such as customer details must be kept safe with strong passwords and backup copies.
• Computer Memory: Units, Primary and Secondary, Data Recovery – Computers store everything as bits (0 or 1). 8 bits make a byte, and each bigger unit is 1024 times the one before. Primary memory (RAM, ROM, cache) works directly with the CPU; secondary storage (HDD, SSD, pen drive) keeps files for a long time. A deleted file can often be recovered until it is overwritten, so data must be protected.
• Computer Networks: Types, Devices and Topologies – A computer network is a group of devices connected to share data and resources. By area, networks are PAN, LAN, MAN and WAN. Devices do different jobs: a modem converts digital and analog signals, a repeater boosts a weak signal, a hub sends data to all ports, a switch sends it only to the right device, a router joins networks and chooses a path, and a gateway joins networks that use different protocols. Topology is the layout of connections: star, bus, tree and mesh, each with its own strengths and weaknesses.
• Computers and Computing: Evolution, Parts and I/O Devices – A computer is an electronic machine that takes input, processes it under the control of a program, stores data and gives output. Computing devices grew from the abacus to smartphones. Every computer has an input unit, a CPU, memory and an output unit, joined by buses and ports.
• Control Statements in Python: if-else, while and for – Normally Python runs lines one after another (sequence). Control statements change this flow. if-else chooses one of two paths; if-elif-else picks the first true condition from many. while repeats a block while a condition is true; for repeats once for each item of a sequence such as range(start, stop, step).
• Corporate Activities and Information Processing – Data are raw facts. Information processing collects data, sorts and counts it and shows it clearly, so people can decide. Companies use it in sales, buying, pay and planning. Good communication uses clear information design: one message, simple chart, honest labels. Information ethics means respecting privacy, truth, ownership and permission when we handle information.
• Cyber Crime and the Indian IT Act – Cyber crime is any crime that uses a computer, phone or the internet. Common ones are hacking, phishing, cyber bullying, identity theft and ransomware. India's Information Technology Act, 2000 (amended in 2008) gives legal punishment for them. Victims can report at cybercrime.gov.in or call 1930.
• Data Visualization with Matplotlib: Line, Bar and Histogram – Data visualization means showing data as pictures such as charts, so that patterns are easy to see. In Python we use the pyplot module of Matplotlib, imported as plt. A line plot shows change over time, a bar graph compares separate groups and a histogram shows how values are spread over ranges called bins. A chart becomes clear with a title, axis labels and a legend, and plt.savefig() saves it as an image file.
• Database Concepts: DBMS, Relations and Keys – Keeping data in separate files causes duplication, inconsistency and poor security. A database stores related data in one organised place, and a DBMS (like MySQL) is the software that manages it. In the relational model, data is kept in tables (relations) made of columns (attributes) and rows (tuples); a domain is the set of allowed values of a column. A candidate key uniquely identifies each row; one is chosen as the primary key and the others are alternate keys.
• Dictionaries in Python: Key-Value Pairs and Methods – A dictionary is a mutable collection of key: value pairs in curly braces, like {"Ravi": 85}. Keys are unique and immutable; values can be anything. We add or change a pair with d[key] = value, read with d[key] or d.get(key), traverse with for k in d, and use methods such as keys(), values(), items(), update(), pop(), popitem() and clear().
• Digital Footprint, Net Etiquette, IPR and FOSS – Everything we do online leaves a digital footprint. Good citizens follow net etiquette, protect personal data and respect other people's intellectual property. Copying without credit is plagiarism. Licences decide how we may use software and content; FOSS gives the freedom to use, study, change and share.
• E-waste and the Health Effects of Technology – E-waste is discarded electronic equipment. It contains toxic metals like lead, mercury and cadmium that harm soil, water, air and people when dumped or burnt. We manage it by Reduce, Reuse and Recycle through authorised recyclers, backed by India's E-Waste (Management) Rules. Using devices too long also harms eyes, posture, wrists, sleep and mood; good ergonomics and breaks keep us healthy.
• Emerging Trends: AI, IoT, Cloud and Blockchain – Emerging technologies are new tools that are changing how we live and work. AI lets machines do smart tasks; machine learning lets them learn from data; NLP lets them use human language. AR adds virtual things to the real world, VR replaces it. Robots sense, think and act. IoT devices with sensors create big data, which smart cities use. Cloud computing rents out IaaS, PaaS or SaaS over the internet; grid computing joins many computers for one big job. Blockchain keeps a shared record that is very hard to change secretly.
• Internet and Web: URL, Services, Websites, Hosting and Browsers – The Internet is a worldwide network of networks. The World Wide Web is the collection of web pages on it, linked by hyperlinks, and each page has an address called a URL. The Internet also carries email, chat and VoIP. A website is a group of related web pages; pages can be static (same for everyone) or dynamic (built for each visitor). A web server stores and sends pages, and web hosting keeps a site online. A browser displays pages, and its settings, add-ons, plug-ins and cookies change how it works.
• Introduction to NumPy: Creating Arrays from Lists – NumPy (Numerical Python) is a library for fast maths on arrays. An array is a grid of items that all have the same type. We make one from a list with np.array(list); a list of lists gives a 2-D array. Attributes ndim, shape, size and dtype describe it. Unlike lists, arrays do maths on every item at once.
• Lists in Python: Create, Traverse, Change and List Methods – A list is an ordered, changeable collection written in square brackets, like [10, 20, 30]. Items are reached by index (from 0, or negative from the end) and slices. We traverse a list with a for loop, change items in place because lists are mutable, and use functions (len, max, min, sum, sorted, list) and methods (append, insert, extend, remove, pop, sort, reverse, count, index, clear) to work with it.
• Pandas DataFrame: Working with a Whole Table – A DataFrame is a two-dimensional table in pandas, with labelled rows (the index) and labelled columns. Every column is a Series. You can build one from a dictionary of Series, from a list of dictionaries or by reading a CSV file. You can display it, walk through it row by row or column by column, add, select, delete and rename rows and columns, pick data with loc, iloc or a condition, and save it back to a CSV file.
• Pandas Series: One Labelled Column of Data – Pandas is a Python library for working with data in tables, and Matplotlib is a library for drawing charts. A Series is one column of values where every value has a label called its index. You can make a Series from a list or NumPy array, from a dictionary or from a single scalar value. Maths between two Series matches labels, and a label present in only one gives NaN. head() and tail() show the first or last rows, and you can pick values by label, by position, by slice or by a condition.
• Python Basics: Modes, Variables, Data Types and Operators – Python runs in interactive mode (one line at a time) or script mode (a saved .py file). Blocks are shown by indentation. Variables are names tied to values; every value has a data type, and some types are mutable. Operators build expressions that Python works out by precedence. input() reads text, int()/float()/str() convert types, and debugging fixes syntax, runtime and logical errors.
• Software: System and Application, Generic and Specific – Software is a set of programs. System software (operating system, device drivers, utilities, language translators) runs and looks after the computer. Application software does a user's task. Application software can be generic (general-purpose, ready-made for many users) or specific-purpose (customised for one organisation's need).
• SQL Aggregates, GROUP BY, HAVING, ORDER BY and Equi-Join – Aggregate (multi-row) functions take many rows and return one value: MAX, MIN, SUM, AVG and COUNT. They skip NULL values, except COUNT(*), which counts every row. GROUP BY splits rows into groups with the same value so an aggregate runs once per group. HAVING filters those groups, while WHERE filters single rows before grouping. ORDER BY sorts the output in ascending or descending order. An equi-join combines two tables by matching rows where a common column is equal.
• SQL Single-Row Functions: Maths, Text and Date – A single-row function takes one value from a row and returns one value, so a column of n rows gives n answers. Maths functions: POWER, ROUND and MOD. Text (string) functions: UPPER, LOWER, LENGTH, LEFT, RIGHT, SUBSTR, INSTR and TRIM. Date functions: NOW, DATE, MONTH, MONTHNAME, YEAR, DAY and DAYNAME. They are used inside SELECT, WHERE and ORDER BY.
• SQL with MySQL: Create Tables, Change Rows and Ask Questions – SQL (Structured Query Language) is the language used to talk to a relational DBMS like MySQL. DDL commands (CREATE, ALTER, DROP) define tables; DML commands (INSERT, UPDATE, DELETE) change rows; DQL (SELECT) reads data. Each column has a data type such as INT, FLOAT, CHAR, VARCHAR or DATE. SELECT … WHERE filters rows using relational operators, BETWEEN, AND/OR/NOT and IS NULL.