List Manipulation

List Manipulation

1. Definition

   • Collection of items
     • Ordered
     • Mutable
     • Allows duplicates

2. Creating Lists

   • Using square brackets
     • Example: my_list = [1, 2, 3]
   • Using the list() constructor
     • Example: my_list = list((1, 2, 3))

3. Accessing List Elements

   • Using index
     • Starts at 0
     • Negative indexing for reverse
   • Slicing
     • Subsets of lists
     • Example: my_list[1:3]

4. Nested Lists

   • Lists within lists
     • Multi-dimensional arrays
       • Example: l=[12,[34,56],78,90]
   • Accessing elements
     • my_list[0][1] for first sub-list
     • Iterating through nested lists

5. List operations

   • Concatenation
     • Using the `+` operator
       • Example: `list1 + list2`
   • Replication
     • using the multiplication operator
       • syntax: list * n
   • Slicing
     • Extracting a portion of a list
       • Syntax: `list[start:end:step]`

6. Built-in function

   • len()
     • Function to return the number of items
       • syntax: len(list_name)
   • list()
     • Creates a list in Python.
   • append()
     • Append an element to the end
       • Syntax: list.append(item)
   • extend()
     • Method to add multiple elements
       • Syntax: list.extend(iterable)
   • insert()
     • Insert an element at a specific index
       • Syntax: list.insert(index, element)
   • count()
     • Returns the number of occurrences
       • Syntax: list.count(element)
   • index()
     • Returns the index of an element
       • Syntax: list.index(element)
   • remove()
     • Removes the first occurrence of a value
       • Syntax: list.remove(value)
   • pop()
     • Removes the last item from a list Returns the item that was removed
     • Can remove an item at a specific index
     • Syntax: list.pop([index])
   • reverse()
     • Reverses the order of elements
       • Syntax: list.reverse()
   • sort()
     • Used for arranging elements
       • Modifies the original list
       • Syntax: list.sort()
   • sorted()
     • Sorts elements of a list
     • Returns a new sorted list
     • Syntax: sorted(iterable, key=None, reverse=False)
   • min()
     • Returns the smallest item
       • Syntax: min(list)
   • max()
     • Finds the largest item
       • Syntax: max(list)
   • sum()
     • Adds numerical values in a list
       • Syntax: sum(list)