String Tools.

Second class. You can already read characters. Now come basic tools for the whole string.

len(text) returns the character count (spaces included). The in operator checks whether a substring appears: "Lab" in msg is True or False.

Methods return a new string (the original does not change unless you reassign): - upper() / lower() — uppercase / lowercase - find(sub) — index of the first match, or -1 if missing - replace(old, new) — replaces occurrences of old with new

Mini example:

msg = "Hi Lab"
print(len(msg))
print("Lab" in msg)
print(msg.upper())
print(msg.find("Lab"))
print(msg.replace("Lab", "World"))

Common mistake: expecting msg.upper() to change msg without assignment; or confusing find with a list index. We do not use strip, split, or join yet — that is the next lesson.