--- title: "Online Coding and Python Classes in Castle Hill, Sydney" description: "Live online coding and Python classes for Castle Hill children, teenagers and adults: Scratch at six, Python data projects later. First lesson free." canonical: https://learn.modernagecoders.com/online-coding-and-python-classes-in-castle-hill-sydney source: src/pages/online-coding-and-python-classes-in-castle-hill-sydney.html --- > Live online coding and Python classes for Castle Hill children, teenagers and adults: Scratch at six, Python data projects later. First lesson free. Skip to contentCourse picks for Castle Hill ## Python courses built around real data Each course reaches dictionaries and sets, the tools in this page's project. The free trial lesson decides the starting point, with no card details asked for. [![Python and AI for Kids course thumbnail](/images/python-kids.webp)Ages 8 to 12Python and AI for KidsFirst Python: lists, simple dictionaries and games that remember things.See the syllabus](/courses/python-ai-kids-masterclass)[![Python for Teens course thumbnail](/images/python-teens.webp)Ages 12 to 17Python for TeensDictionaries, sets and the collections module, applied to real public files.See the syllabus](/courses/python-complete-masterclass-teens)[![Data Structures & Algorithms Course course thumbnail](/images/dsa-college.webp)Ages 16 to adultData Structures & Algorithms CourseHash maps, sets and graphs, and when a one-to-one mapping is the wrong model.See the syllabus](/courses/data-structures-algorithms-masterclass-college)[![Python Masterclass course thumbnail](/images/python-college.webp)University and adultPython MasterclassFrom beginner to confident Python for data cleaning, automation and reporting.See the syllabus](/courses/python-programming-masterclass-zero-to-advanced-college) Browse the [course atlas](/course-atlas) for more than one hundred options and use the [coding roadmap](/coding-roadmap) to check prerequisites. The four we are known for ### Python, AI, vibe coding and agentic coding These run underneath everything above. Every one is live and online, placed by ability rather than by age, and the first class is free. [![Vibe Coding for Teens course thumbnail](/images/vibe-coding-teens.webp)Vibe codingAges 13 to 17Vibe Coding for TeensPython, web and AI projects where the learner still owns the thinking.See the syllabus](/courses/vibe-coding-for-teens-python-web-ai-projects-course)[![Python Automation Course course thumbnail](/images/python-college.webp)Python and AICollege and adultPython Automation CourseAutomate the work you already do, then let AI carry part of it.See the syllabus](/courses/python-ai-automation-masterclass-college)[![AI and Machine Learning for Teens course thumbnail](/images/ai-ml-teens.webp)AI and MLAges 14 to 18AI and Machine Learning for TeensTrain a model, read what it learned, and be able to say why it is wrong.See the syllabus](/courses/ai-ml-masterclass-teens)[![Codex & Claude Code course thumbnail](/images/codex-claude-code-adults.webp)Agentic codingProfessionalsCodex & Claude CodeRun AI coding agents on real work without losing control of the codebase.See the syllabus](/courses/codex-and-claude-code-ai-coding-agents-masterclass-for-adults-professionals)Castle Hill in the Census ## A suburb of family houses that spans two councils QuickStats from the statistics bureau for the Castle Hill suburb and locality, against New South Wales and Australia. | Measure | Value | | --- | --- | | People | 40,874 | | Families | 11,503 | | All private dwellings | 14,345 | | Average people per household | 3 | | Suburb area | About 18.8 square kilometres | | Indicator | Castle Hill | NSW | Australia | | --- | --- | --- | --- | | Separate houses among occupied homes | 73.7% (9,748) | 65.6% | 72.3% | | Couple families with children | 55.8% (6,423) | 44.7% | 43.7% | | Bachelor degree or higher | 42.9% (14,244) | 27.8% | 26.3% | | Managers among employed residents | 19.5% (3,770) | 14.6% | 13.7% | | Residents aged 15 to 19 | 6.7% (2,739) | 5.7% | 5.7% | ### Mostly family houses Nearly three in four occupied homes are separate houses, with flats or apartments at 15.3% and townhouses at 10.9%. ### Lots of school-age learners Children aged 10 to 14 made up 7.9% of residents and teenagers aged 15 to 19 6.7%, both above the state shares. ### Two councils Our check of the bureau's 2021 boundaries puts most of the suburb in The Hills Shire and a smaller part in Hornsby Shire. Castle Hill is a suburb rather than a council, so these numbers describe the suburb itself. The bureau adjusts small cells for privacy, so table parts may not reach published totals, and we never add them up to make one. Signature project ## One suburb, two councils: a Python dictionary that cannot cope The education department's school location file gives each school a suburb and a council. We used only those two address columns from its 2,210 rows. | School | Council in the file | First teacher | | --- | --- | --- | | Castle Hill Public School | The Hills | 1880 | | Castle Hill High School | The Hills | 1963 | | Excelsior Public School | The Hills | 1971 | | Samuel Gilbert Public School | The Hills | 1986 | | Oakhill Drive Public School | Hornsby | 1992 | | Approach | Suburbs found in two councils | Schools given the wrong council | | --- | --- | --- | | Plain dict, raw suburb text | Cannot tell | 21 if the last row wins, 23 if the first | | Plain dict, spaces and case cleaned | Cannot tell | 33 if the last row wins, 32 if the first | | defaultdict(set), raw suburb text | 18 | None, but variants split | | defaultdict(set), spaces and case cleaned | 25 | None | ### The quiet overwrite lookup[suburb] = council replaces the old value every time, so the answer for Castle Hill depends on which school happens to come last. Nothing warns you. ### Collect, do not replace councils = defaultdict(set) and councils[suburb].add(council) keep every value. Castle Hill ends up holding both The Hills and Hornsby. ### Clean the keys first The raw file has 1,620 suburb spellings; collapsing spaces and case leaves 1,328. Castle Hill itself is stored with a trailing space. ### Castle Hill is not alone Twenty-five suburb names point to two councils once the text is cleaned, among them Glenorie, Rouse Hill, Wahroonga, North Turramurra, West Ryde and Lane Cove. Together they hold 81 schools, which is why the overwrite bug reaches 33 of them statewide. Only school addresses are used: the suburb and council columns of the department's file. The counts of suburbs, keys and mislabelled schools are our own Python results, not departmental figures. After the fix ## More questions the inverted mapping can answer Once councils[suburb] is a set, a learner can turn the data round again and keep going. | Question | Python idea | Result on the file | | --- | --- | --- | | How many councils appear? | len of a set of values | 129 council names | | Which suburbs does each council cover? | Invert again into council to set of suburbs | Hornsby 22 names, The Hills 16 | | Which suburbs are shared? | A comprehension filtering len(s) > 1 | 25 suburb names | | Which council pairs share most? | Counter over frozenset pairs | A good open exercise | ### Teenagers Read the CSV, build both lookups, and print every school the plain dictionary gets wrong. ### University students Discuss one-to-many and many-to-many relationships, and how a database would model suburbs and councils. ### Adults Check the lookup tables in your own spreadsheets and scripts for the same silent overwrite. The NSW Department of Education and the statistics bureau publish these open files and are not connected with Modern Age Coders; every count above comes from our own scripts. School year ## The 2027 school calendar for Castle Hill learners Lessons pause in the NSW school holidays, so the calendar shapes the class timetable. ### Summer break In the Eastern division, the summer holidays run from Friday 18 December 2026 to Wednesday 27 January 2027. ### Back to school Students return for Term 1 on Wednesday 3 February 2027, after school development days for staff. ### Our timetable Regular weekly classes pick up again once Term 1 is under way, at the time agreed for each learner. An address detail worth noticing Sorting the five first-teacher dates is a quick warm-up: Castle Hill Public School is the oldest at 1880, and the Hornsby-listed Oakhill Drive Public School is the newest at 1992. Learning ladder ## From Scratch lists to Python dictionaries and sets The ages are approximate; the free first lesson finds the right rung. Ages 6 to 10 ### Scratch and lists Games that keep lists of scores and names, the first taste of storing data. [Scratch Coding for Kids](/courses/scratch-programming-complete-course)[Problem Solving and Computational Thinking for Kids](/courses/problem-solving-and-computational-thinking-for-kids)Ages 10 to 13 ### Python basics Variables, loops, lists and simple dictionaries, written and tested by hand. [Python and AI for Kids](/courses/python-ai-kids-masterclass)[Maths Through Coding](/courses/maths-through-coding)Ages 13 to 18 ### Data structures Sets, dictionaries, the collections module and real CSV files. [Python for Teens](/courses/python-complete-masterclass-teens)[Data Science for Teens](/courses/data-science-course-for-teens-python-data)University and adult ### Modelling relationships Hash maps, graphs and databases, and choosing the right structure for messy data. [Data Structures & Algorithms Course](/courses/data-structures-algorithms-masterclass-college)[Python Masterclass](/courses/python-programming-masterclass-zero-to-advanced-college)Coding and AI ## Would an AI assistant have caught the Castle Hill bug? Often not, unless the person asking knows to look for it. Ask an assistant for a suburb-to-council lookup and the most common answer is a plain dictionary built in a loop, the exact code that mislabels Oakhill Drive Public School. It runs cleanly and returns a tidy result, so the mistake hides. A learner who has inverted the mapping knows to ask whether any key can have more than one value, and can prompt for, or write, the defaultdict(set) version. Understanding data structures is what turns AI-written code from a guess into something checked. In 2026 code is cheap to generate; Castle Hill learners who understand why one suburb can belong to two councils write code that respects the real world. The longer argument is in [why teenagers should still learn to code in 2026](/blog/is-coding-worth-learning-2026). Delivery ## Live online, whichever council your street is in The Hills Shire side or the Hornsby side, every Castle Hill learner joins the same live video lesson from home. ### Real-time teaching A teacher on video follows the learner's screen and corrects mistakes the moment they appear. ### Built around NSW Lessons use NSW stage and syllabus language, and stop for state school holidays. ### Free trial The opening lesson is a full class at no charge, ending with a suggested course, level and time. ### Same-level groups Groups of fifteen to twenty learners of similar ability, or individual lessons where preferred. ### Regular schedule Two lessons a week at fixed times, roughly eight a month, with breaks planned ahead. ### Teachers in India A 4:15pm Castle Hill lesson in summer is 10:45am India time, and 11:45am once Sydney leaves daylight saving. Two time zones Sydney daylight saving runs from Sunday 4 October 2026 to Sunday 4 April 2027; India does not change its clocks. That moves the gap between 5 hours 30 minutes and 4 hours 30 minutes, and our times are always given in Sydney time. Fees ## Castle Hill lesson fees Straightforward prices, identical for every course. First class**USD 0** One whole lesson free, with a course and timetable suggested at the end. Group tuition**USD 100** Two weekly lessons for a month, about eight, with fifteen to twenty learners at one level. Private tuition**USD 150** One-to-one teaching at the same rhythm, around eight lessons a month. Outside India we invoice in US dollars, so Castle Hill households on either side of the council line pay the same. Payment starts only after the trial agrees a course and time; the pricing page sets out breaks, missed lessons and format changes. Request placement[Check availability](https://wa.me/919123366161?text=Hello%20Modern%20Age%20Coders%2C%20we%20would%20like%20a%20free%20coding%20or%20Python%20lesson%20for%20a%20learner%20in%20Castle%20Hill.)Reviews ## What parents write on Google Rated 4.9 across 547 Google reviews. These are real reviews, reproduced as written. ★★★★★ "The one step solution for my son. Modern Age Coders make learning coding so simple that kids love it. The teachers explain complex concepts clearly with practical exercises and interactive content." Ria Mukherjee Parent ★★★★★ "Modern Age Coders has been a game-changer for me. I struggled to grasp IT concepts and coding before joining, but their classes transformed everything. I can now confidently write complex programs with ease." Samriddha Mondal Student ★★★★★ "One of the most wonderful education centres out there. Education is not limited to school syllabus but focuses on skill development." Vansh Agarwal Student ★★★★★ "My child Dhairya is really enjoying the Modern Age Coders classes. This is his first online class and he eagerly looks forward to it. I can already see his improvement, and the teachers are very cooperative." Sonam Oswal Parent of Dhairya ★★★★★ "Modern Age Coders have wonderful teachers who teach in a clear, easy and practical way. The teacher boosts students' confidence and inspires them to learn without hesitation." Sonu Goyal Parent ★★★★★ "I highly recommend this computer coding class! The teachers are incredibly knowledgeable and passionate about coding." Ritu Kedia Parent Free placement class ## Start with an age and an interest That lets a teacher prepare a fitting first lesson. A seven-year-old might build a Scratch game with a high-score list; a teenager or adult might load the school file in Python and find the suburbs shared by two councils. ### Want a class sooner? Book a priority demo A priority demo is a full class of about 45 to 60 minutes. After the class the mentor sends a written skill report and a personal learning roadmap on WhatsApp. If you enrol, the demo fee is adjusted against your first month's fee. Share your demo Order ID with us on WhatsApp and we take it off. [Book a priority demo](/book-demo) ### Contact the team directly WhatsApp or call [+91 91233 66161](tel:+919123366161), or email [connect@modernagecoders.com](mailto:connect@modernagecoders.com). This is Modern Age Coders' actual contact, an Indian number, and not an invented Castle Hill one. [WhatsApp Modern Age Coders](https://wa.me/919123366161?text=Hello%20Modern%20Age%20Coders%2C%20we%20would%20like%20a%20free%20coding%20or%20Python%20lesson%20for%20a%20learner%20in%20Castle%20Hill.) Submitted details are used for placement and follow-up. FAQ ## Castle Hill coding and Python questions What Castle Hill families usually want to know. ### How many people live in Castle Hill? The 2021 Census QuickStats for the Castle Hill suburb and locality counted 40,874 people, with a median age of 42 and 11,503 families. ### Is Castle Hill in The Hills Shire or Hornsby Shire? Both. Our check against the statistics bureau's 2021 boundaries places most of the suburb in The Hills Shire and a smaller part in Hornsby Shire, and the education department lists one Castle Hill school under Hornsby. ### What is defaultdict(set) in Python? It is a dictionary from the collections module that creates an empty set the first time a key is used. Adding values to that set keeps all of them, which suits one-to-many data such as a suburb with two councils. ### What does the Castle Hill project find? With suburb spellings cleaned, a plain dictionary from suburb to council mislabels 33 NSW government schools, including Oakhill Drive Public School. Building sets instead reveals 25 suburb names shared by two councils. ### Does the course help with HSC subjects? Teachers follow NSW syllabus terms and can explain programming ideas met in senior subjects, while all assessed work stays the student's own. ### What age can a child start? Six is a good age to begin with Scratch. Python projects like this one usually start around 12 or 13. ### What equipment is needed? A laptop or desktop computer with a microphone, speakers or headphones, and a reliable internet connection. Tablets are not ideal for typing Python. ### Do you teach in Castle Hill in person? No. We teach only online and have no premises in Australia, including Castle Hill. Our contact phone number is an Indian one. ### What do online coding classes cost for Castle Hill learners? The first lesson is free. Group classes are USD 100 a month for two live lessons a week, about eight each month, with fifteen to twenty learners; one-to-one costs USD 150 a month on the same plan. No payment is taken until the course and time are agreed. ### How large are the groups? Fifteen to twenty learners, grouped by level and goals rather than age. If no group fits the learner's availability, one-to-one lessons are offered. Nearby guides ## More for Castle Hill learners Castle Hill sits across two council pages: [coding and AI classes in The Hills Shire](/best-coding-and-ai-classes-in-the-hills-shire-sydney) and [online coding and Python classes in Hornsby](/online-coding-and-python-classes-in-hornsby-sydney). For the whole city see [coding classes in Sydney](/best-coding-classes-in-sydney), and children leaving Scratch behind can read [after Scratch: the next step to Python](/after-scratch-next-step-python-australia). Book the free class[Book a priority demo](/book-demo)[Send a WhatsApp](https://wa.me/919123366161?text=Hello%20Modern%20Age%20Coders%2C%20we%20would%20like%20a%20free%20coding%20or%20Python%20lesson%20for%20a%20learner%20in%20Castle%20Hill.)Free class[Priority demo](/book-demo)[Call us](tel:+919123366161) ## Keep exploring Modern Age Coders ### Related courses and guides - [Online Coding and Python Classes in Castleford, West Yorkshire](/online-coding-and-python-classes-in-castleford) - [Online Coding and Python Classes in Casey, Melbourne](/online-coding-and-python-classes-in-casey-melbourne) - [Online Coding and Python Classes in Cheltenham](/online-coding-and-python-classes-in-cheltenham) - [Online Coding and Python Classes in Carlingford, Sydney](/online-coding-and-python-classes-in-carlingford-sydney) - [Online Coding and Python Classes in Chermside, Brisbane](/online-coding-and-python-classes-in-chermside-brisbane) - [Online Coding and Python Classes in Canning Vale, Perth](/online-coding-and-python-classes-in-canning-vale-perth) - [Python Classes Online in Australia](/python-classes-online-australia) - [Online Coding and Python Classes in Sandy Bay, Hobart](/online-coding-and-python-classes-in-sandy-bay-hobart) - [Online Coding and Python Classes in Palmerston, Darwin](/online-coding-and-python-classes-in-palmerston-nt-darwin) ### Learn more - [Coding Classes for 10 Year Olds Online: Scratch to Python](/coding-for-10-year-olds) - [Coding for Class 5: Python, Scratch & AI Tools for 10 Year Olds](/coding-for-class-5) - [Python to AI Roadmap for Students in the Netherlands](/python-to-ai-roadmap-for-students-netherlands) - [Coding Classes for 9 Year Olds: Scratch Games and First Python](/coding-for-9-year-olds) ### Free resources - [Python Tutorial for Beginners: Complete Guide](/resources/python) - [Modules and Packages in Python](/resources/python/modules-and-packages) - [Scope, LEGB Rule, and Closures](/resources/python/scope-and-closures) - [Tuples in Python](/resources/python/tuples-in-python) ### From the blog - [Python Tutorials & Guides](/blog/topic/python) - [Python List Comprehension: 15 Examples, Simple to Advanced](/blog/python-list-comprehension-explained) - [How to Read and Write Files in Python (The Complete Guide)](/blog/how-to-read-and-write-files-in-python) - [Python OOP Tutorial: Classes, Objects, and Inheritance](/blog/python-oop-tutorial-for-beginners) ### Start here - [About Modern Age Coders, teaching since 2020](/about) - [Modern Age Coders pricing, one honest price per plan](/pricing) --- *Canonical: https://learn.modernagecoders.com/online-coding-and-python-classes-in-castle-hill-sydney*