Methods Reference 🚀

Prerequisites: Python Data Structures

Mentor's Note: Methods are like the "Special Moves" of an object. A String has different moves than a List. Use this page whenever you forget the exact name of a move! 💡

---

🌟 The Scenario: The Multi-Tool 🛠️

Imagine you have a high-tech tool that changes its heads.

• The Logic:
  • When you attach the String Head 🔡, you can upper() (Scale) or strip() (Clean).
  • When you attach the List Head 🛍️, you can append() (Add) or sort() (Arrange).
• The Result: You use the same tool (Your Code) but switch "Heads" (Methods) based on the data you are handling. ✅

---

📖 Essential Methods by Type

1. String Methods (The Cleaners) 🔡

Remember: These return a NEW string. - .upper() / .lower(): Change case. - .strip(): Remove leading/trailing spaces. 🧹 - .replace(old, new): Swap parts of the text. - .split(sep): Break a string into a List.

2. List Methods (The Organizers) 🛍️

Remember: These change the ORIGINAL list. - .append(x): Add item to the end. - .insert(i, x): Add at a specific spot. - .pop(i): Remove and return an item. - .sort(): Put in alphabetical/numeric order.

3. Dictionary Methods (The Librarians) 📖

• .keys(): Get all the labels.
• .values(): Get all the data.
• .get(key, default): Safely look up a value without crashing. 🛡️

---

🎨 Visual Logic: Mutability Check

graph LR
    A[String: 'Hi'] -- .upper --> B[New Object: 'HI']
    C[List: 1, 2] -- .append 3 --> D[Same Object: 1, 2, 3]

    style B fill:#dfd
    style D fill:#ddf

---

💻 Implementation: Method Lab

Python (3.10+)

# 🚀 Action: Chaining methods together

# 🛒 Scenario: Cleaning user input
raw_input = "  VISHNU_DIGITAL  "

# 🧹 Clean -> Lowercase -> Replace
clean_name = raw_input.strip().lower().replace("_", " ")

print(f"Final Name: '{clean_name}' ✅")
# Output: 'vishnu digital'

---

📊 Sample Dry Run (Dictionary .get)

Goal: Look for 'age' in D = {"name": "VD"}

Step	Instruction	Logic	Result
1	D["age"]	Direct access	CRASH 💥 (KeyError)
2	D.get("age", 0)	Safe access	0 (Returns default) 🛡️

---

💡 Interview Tip 👔

"Interviewers love asking: 'Why can't we sort a string in-place?' Answer: Because Strings are Immutable! You have to convert them to a list, sort, and join them back."

---

💡 Pro Tip: "Good names are the best documentation. If you name your variables well, your code tells a story." - Anonymous

---

← Back: Built-in Reference | Next: Python MCQs →