Lists Data Structures and Algorithm.pptx

Lists Data Structures and Algorithm.pptx

• 1.
  Python List
• 2.
  Python List mylist =["apple", "banana", "cherry"] List • Lists are used to store multiple items in a single variable. • Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage.
• 3.
  Python List • Listsare created using square brackets: E.g.
• 4.
  List Items • Listitems are ordered, changeable, and allow duplicate values. • List items are indexed, the first item has index [0], the second item has index [1] etc.
• 5.
  Ordered • When wesay that lists are ordered, it means that the items have a defined order, and that order will not change. • If you add new items to a list, the new items will be placed at the end of the list.
• 6.
  Changeable • The listis changeable, meaning that we can change, add, and remove items in a list after it has been created. • Change • Add
• 7.
  Changeable • Remove • Wehave four types – remove, pop, del, clear • Del • The remove() method removes the specified item. • Pop • The pop()method removes the specified index. • If you do not specified the index, the pop() method removes the last item.
• 8.
  Changeable • Remove • Wehave four types – remove, pop, del, clear • Del • del keyword also removes the specified index. • The del keyword can also delete the list completely.
• 9.
  Changeable • Remove • Wehave four types – remove, pop, del, clear. • Clear • The clear() method empties the list. • The list still remains, but it has no content.
• 10.
  Allow Duplicates • Sincelists are indexed, lists can have items with the same value. Example Lists allow duplicate values:
• 11.
  List Length • Todetermine how many items a list has, use the len() function: Example Print the number of items in the list:
• 12.
  List Items -Data Types • List items can be of any data type: Example String, int and boolean data types: A list can contain different data types:
• 13.
  List Items -Data Types • List items can be of any data type: Example String, int and boolean data types: A list can contain different data types:
• 14.
  List Items -Data Types • type() • From Python's perspective, lists are defined as objects with the data type 'list’: <class 'list'>
• 15.
  The list() Constructor •It is also possible to use the list() constructor when creating a new list. Example • Using the list() constructor to make a List: