Day 15: String Operations — Playing With Text!

Strings Are Like LEGO Blocks

You know how LEGO blocks snap together to build something bigger? Strings work the same way! Take small pieces of text and connect them into one big message. Every notification, every chat message, every personalised greeting in every app is built this way!

Joining Strings — Concatenation

first = "Hello"
second = "Rohith"

message = first + " " + second
print(message)

Output: Hello Rohith. The + joins them together. The " " in the middle adds a space. Without it you'd get "HelloRohith" — no gap!

Real World Connection

When WhatsApp shows "Priya is typing...", it joins the name + " is typing...". When Swiggy says "Your order from McDonald's is on the way!", it joins your order details into one message. When Instagram says "Rohith liked your photo", it's just strings joined together!

f-Strings — The Easier Way

name = "Rohith"
age = 21

message = f"Hello {name}, you are {age} years old!"
print(message)

Output: Hello Rohith, you are 21 years old! Put f before the quote, then use { } to drop variables straight into the text. Way cleaner than using + everywhere. This is how professionals write it!

More String Operations

name = "  Rohith  "

print(name.strip())
print(name.replace("Rohith", "Priya"))
print("Rohith".count("h"))

strip() cleans messy spaces — used when users accidentally type spaces in forms. replace() swaps words — used in chat apps and search tools. count() counts letters — used in password checkers!

Common Mistakes

Mistake 1 — Joining text with a variable without quotes.

"Hello" + Rohith
"Hello" + "Rohith"

Mistake 2 — Forgetting the space between words.

name = "Rohith"
print("Hello" + name)
print("Hello " + name)

Mini Challenge

Quick Quiz

Q: What does + do with strings? A: Joins them together — "Hello" + "World" = "HelloWorld"!

Q: What's the easier way to put variables inside strings? A: f-strings! f"Hello {name}"

Q: How do you remove extra spaces from a string? A: .strip() — name.strip()!

Key Takeaways