6. List, Tuple, Set, Dictionary (1).pptx

List, Tuple, Set, Dictionary Objective Able to write programs using list, tuple, dictionary and set List Introduction Using a list, a programmer can use a single variable to store all the elements of the same or different data type and even print them. A list is a sequence of values call...

List, Tuple, Set, Dictionary Objective Able to write programs using list, tuple, dictionary and set List Introduction Using a list, a programmer can use a single variable to store all the elements of the same or different data type and even print them. A list is a sequence of values called items or elements. The elements can be of any type. A list is mutable in nature; the contents can be changed. The user can increase or decrease its size; thus it is dynamic in nature. The elements are placed within a square bracket, differentiated by a comma separator. Creating of List Objects The list class defines lists. A programmer can use a list’s constructor to create a list. The empty list object can be created as follows: Creating of List Objects (with Dynamic Input) Creating of List Objects (with list function) Creating of List Objects (with split() function) Accessing Elements of a List The elements of a list are unidentifiable by their positions. Hence, the index[] operator is used to access them. Accessing Elements of a List (By using an index) Accessing Elements of a List (By using a slice operator) List vs Mutability After the creation of a list, you can modify its contents; hence it is mutable in nature. Traversing the Elements of a List Traversal means to access the elements of a list sequentially. Traversing the Elements of a List Important Functions of a List Getting the information about the list len() count() index() Important Functions of a List Manipulating Elements of a List append() - This function is used to add new items at the end of a list insert() - It is used to insert an item at a specified index position. Important Functions of a List Manipulating Elements of a List Important Functions of a List Manipulating Elements of a List extend() - add the items of a list into another list Important Functions of a List Manipulating Elements of a List remove() - remove particular items from the list pop() – remove and return the last element of the list Important Functions of a List Ordering Elements of a List reverse() – reverses the elements of the list sort() – sorts the elements of data Using Mathematical Operators of List Two operators are used for list objects; + and * Membership Operators Membership operators are used to check whether the element is a member of the list or not. The clear() function The clear() function is used to remove all the elements from the list. Nested list Nested list List comprehensions List comprehension is used to create a new list from existing sequences. It is a tool for transforming a given list into another list. Tuple Introduction A tuple contains a sequence of items of many types. The elements of tuples are fixed. Once a tuple has been created, we cannot add or delete elements or shuffle their order. Tuples are immutable Tuple Creation A tuple is an inbuilt data type in Python. In order to create a tuple, the elements of tuples are enclosed in parenthesis instead of square brackets. Accessing Elements of a Tuple The elements of a tuple can be accessed by the index and slice operator. Tuple vs Immutability A tuple is immutable in nature; you cannot modify the contents of a tuple once created. Mathematical Operators for tuple Important functions of tuple Important functions of tuple Tuple Packing and Unpacking A tuple can be created by packing the set of variables. Set Introduction A set is an unordered collection of unique elements without duplicates. A set is mutable. We can easily add or remove elements from a set. The set data structure in Python is used to support mathematical set operations. Set is an unordered and unindexed collection of items in Python. Unordered means when we display the elements of a set, it will come out in random order. Unindexed means, we cannot access the elements of a set using the indexes like we can do in list and tuples. Create of Set Objects A programmer can create a set by enclosing the elements inside a pair of curly brackets{}. Create of Set Objects Important Functions of a Set Important Functions of a Set Set comprehension The indexing and slicing operations are not supported by set objects. Dictionary Introduction A dictionary is a collection that stores values along with keys. The sequence of such keys and value pairs is separated by commas. These pairs are sometimes called entries. If you wish to show the set of objects as a (key, value) pair, then dictionaries are preferred. Create a Dictionary We can create a dictionary by enclosing the items inside a pair of curly brackets{}. One way to start a dictionary is to create an empty dictionary first and then add items to it. Accessing Data from a Dictionary The data can be accessed using keys. Updating a Dictionary If you wish to add any new (key, value) pair in the already defined dictionary, then the following syntax is used: Deleting Elements from a Dictionary Important Functions of a Dictionary a) len(): It gives the quantity of elements present in the dictionary. b) clear(): It will delete the complete elements from dictionary. c) get(): It will return the associated value of the key if it is present or none will be returned. Important Functions of a Dictionary Important Functions of a Dictionary Dictionary comprehension The comprehension concept is applicable in dictionaries.