Chapter 3: Strings in Python – Theory Notes

✅ Introduction to Strings

name = "Prathamesh"
nameshort = name[0:7]
print("The short version of my name is", nameshort)

character1 = name[1]
print("The second letter of my name is", character1)

📚 Key Concepts:

• Strings in Python are ordered sequences of characters.
• They are zero-indexed, meaning the first character is at index 0.
• name[0:7] includes characters from index 0 to 6 (7 is excluded).
• name[1] gives the second character of the string.

🧠 Learning: Python’s string slicing uses the format string[start:end]

It includes the start index but excludes the end index.

🔁 Negative Indexing

name = "Prathamesh"
print(name[-10:-1])  # Output: rathames
print(name[0:9])     # Output: Prathames

print(name[:4])      # Same as name[0:4] -> "Prat"
print(name[1:])      # Same as name[1:10] -> "rathamesh"
print(name[3:])      # Same as name[3:10] -> "thamesh"

📚 Key Concepts:

• Negative indexes start from the end of the string.
  • 1 is the last character, 2 is second last, and so on.
• name[-10:-1] is same as name[0:9] → This is helpful for reverse-style slicing.
• Python allows partial slicing:
  • [:4] → from start till index 3
  • [3:] → from index 3 to end

🪜 Slicing with Skip Values