Week 11 — Readings & Resources · Strings in Depth & Text Processing

Course: Introduction to Computer Science — CS1 / Programming Fundamentals in Python (CSCI 1101) · Silver Oak University (fictional sample) · Prof. Okafor
Objective covered: Objective 7 — Use the core string methods, explain immutability, and write simple text algorithms.

How to use this page

Everything here is a link to an external resource — open it in your browser. Nothing needs to be downloaded or installed; the Python environments below run in the browser.

This week is hands-on: there's a method for almost every text job, and the only way to learn them is to call them and read what comes back. So keep a Python tab open and run every example you read. The single idea to keep in front of you the whole week: a string method returns a NEW string and never changes the original — when a page (or a chatbot) claims otherwise, prove it by running the code.

Order that matches the lecture: ① the core string methods → ② .split() ↔ .join() and immutability → ③ a method reference to look things up → ④ official docs on text (the source of truth on immutability).

A habit to keep: never trust a method result you didn't run. Before you believe what a method returns — or whether the original changed — paste it into the runner and run it yourself.

① The Core String Methods — start here

Maps to Lecture Segments 2–3. Case, whitespace, search, count, and the all-important .split()/.join().

Read & do — "Python Strings" (Programiz)
🔗 https://www.programiz.com/python-programming/string
Why it's assigned: the cleanest single page on strings — creating them, indexing/slicing (your Week 3 review), the "Strings are Immutable" section that names this week's big idea outright, membership with in, and a table of the core methods (upper, lower, replace, find, split, startswith). Read it with a Python tab open and run each example.
⏱ ~12 min

Run Python in your browser — a free online editor (no install)
🔗 https://www.online-python.com/
Why it earns the click: where you run every method this week. Type " Hello ".strip(), print it, and watch the spaces vanish — then print the original and watch it stay put. (A second option, if you ever want it: 🔗 https://www.programiz.com/python-programming/online-compiler — same idea.)
⏱ 2 min to open and run your first method call

② Immutability + the Whole Method List

Maps to Lecture Segments 4–6. Why methods return a new string, and a reference for every method by name.

Read — "An Informal Introduction to Python" → §3.1.2 Text (official Python Tutorial)
🔗 https://docs.python.org/3/tutorial/introduction.html
Why it's assigned: the source of truth on what we covered. Scroll to §3.1.2 (Text): it shows strings being indexed and sliced and then states plainly that "Python strings cannot be changed — they are immutable," with the exact error you get if you try, and the rule that "if you need a different string, you should create a new one." That is this week in one paragraph, from the people who make Python. (The whole tutorial starts here: 🔗 https://docs.python.org/3/tutorial/index.html — your reference all term.)
⏱ ~8 min

Reference — "Python String Methods" (Programiz)
🔗 https://www.programiz.com/python-programming/methods/string
Why it earns the click: a one-line-per-method index of every string method, each linking to its own page with run-it examples. Bookmark it — when you forget exactly what .find() returns vs. .index(), or what .startswith() checks, this is the fastest lookup. For this week, click into upper, lower, strip, split, join, replace, find, count, and startswith.
⏱ ~6 min (skim now; return as a reference)

③ Practice-on-the-page (interactive)

Maps to the whole week. A click-through method list with a "Try it Yourself" runner on each example.

Interactive — "Python String Methods" (W3Schools)
🔗 https://www.w3schools.com/python/python_strings_methods.asp
Why it earns the click: a friendly, alphabetical table of the string methods, each with a green "Try it Yourself" button so you run the example right on the page. A nice place to drill .upper(), .lower(), .strip(), .split(), .replace(), .count(), and .startswith() without leaving the tutorial.
⏱ ~8 min

See your code run, step by step — Python Tutor
🔗 https://pythontutor.com/
Why it earns the click: paste s = "Hello", t = s.upper(), print(s) and step forward — you'll watch a new string t appear while s stays "Hello". The best way to see immutability instead of just reading about it. We use it in the Coding Lab.
⏱ ~5 min

Pick-one quick path (≈15 min total)

In a hurry? Do exactly these two and you'll be ready for the quiz:
1. Read the "Python Strings" page on Programiz, focusing on the methods table and the "Strings are Immutable" section (groups ①–②).
2. Open online-python.com and run all three: s = "Hello", then s.upper(), then print(s) (see it's still Hello); then print("the cat sat".split()) (a list); then print(" ".join(["the","cat","sat"])) (back to a string).

Heads-up (links rot): these point to outside sites that occasionally move or rename pages. If a link ever fails, tell Prof. Okafor and use the official Python Tutorial (docs.python.org/3/tutorial) or W3Schools (w3schools.com/python) in the meantime.