Python ல் List Operations and Methods

List என்றால் என்ன?

• Ordered மற்றும் mutable collection.
• Multiple data types தாங்கலாம்:
  • Numbers (int)
  • Strings
  • Floats

Basic List Operations

List Creation

• Syntax: my_list = [1, 2, 3, 'apple', 5.5]

Accessing Elements

• Indexing: Elements are accessed via their index (starting from 0).
  • Example: my_list[0] gives 1
• Slicing: Accessing a range of elements.
  • Example: my_list[0:3] gives [1, 2, 3]

Modifying a List

• Lists are mutable, meaning we can change their values.
• Example:
  • Original List: numbers = [10, 20, 30, 40]
  • Modify: numbers[1] = 25

List Concatenation

• Concatenating two lists:
  • Example: list1 = [1, 2, 3]
  • list2 = [4, 5, 6]
  • Result: list1 + list2 gives [1, 2, 3, 4, 5, 6]

Checking Membership

• Checking if an element exists in a list:
  • Example: banana in fruits
  • grape not in fruits

Iterating Over a List

• Using a loop to print each element:
  • Example: for number in numbers: print(number)

List Methods

1. Append

• Adding an element to the end of the list:
  • Example: fruits.append('cherry')

2. Insert

• Inserting an element at a specific index:
  • Example: fruits.insert(1, 'mango')

3. Remove

• Removing first occurrence of a value:
  • Example: fruits.remove('banana')

4. Pop

• Removing and returning an element:
  • Example: number = numbers.pop(1) removes and returns the element at index 1.

5. Index

• Finding the index of an element:
  • Example: fruits.index('banana')

6. Count

• Counting occurrences of an element:
  • Example: fruits.count('apple')

7. Sort

• Sorting the list:
  • Example: numbers.sort()

8. Reverse

• Reversing the list:
  • Example: numbers.reverse()

9. Copy

• Copying a list:
  • Example: copied_list = original_list.copy()

10. Clear

• Clearing the list:
  • Example: numbers.clear()

Other Useful Functions

• len(numbers): Length of the list.
• min(numbers): Minimum value.
• max(numbers): Maximum value.
• sum(numbers): Sum of elements.
• sorted(numbers): Returns sorted list.

Conclusion

• List operations and methods are crucial in Python for data manipulation.
• It is essential to understand these concepts for effective programming.