<h5 id="101-introduction-to-tuples">10.1 INTRODUCTION TO TUPLES</h5> <ul> <li>A tuple is an ordered sequence of elements of different data types, enclosed in parenthesis and separated by commas.</li> <li>Elements of a tuple can be accessed using index values, starting from 0.</li> <li>Example of tuples: <ul> <li>tuple1 = (1,2,3,4,5)</li> <li>tuple2 =(‘Economics’,87,‘Accountancy’,89.6)</li> <li>tuple3 = (10,20,30,[40,50])</li> <li>tuple4 = (1,2,3,4,5,(10,20))</li> </ul> </li> <li>If there is only a single element in a tuple, it should be followed by a comma to be treated as a tuple.</li> <li>A sequence without parentheses is treated as a tuple by default.</li> <li>Tuples are generally used to store elements of different data types.</li> </ul> <p>======</p> <h5 id="1011-accessing-elements-in-a-tuple">10.1.1 Accessing Elements in a Tuple</h5> <ul> <li>Tuples are accessed using indexing and slicing similar to lists or strings.</li> <li>The first element of a tuple can be accessed using index 0. For example, <code>tuple1[0]</code> will return 2.</li> <li>Negative indexing can be used to access elements from the right. For example, <code>tuple1[-1]</code> will return the last element of the tuple.</li> <li>Slicing can be used to access a range of elements. However, assigning values to the sliced portion is not allowed.</li> <li>If an index is out of range, an error will be raised. For example, <code>tuple1[15]</code> will raise an IndexError.</li> </ul> <p>======</p> <h5 id="1012-tuple-is-immutable">10.1.2 Tuple is Immutable</h5> <ul> <li>A tuple is an immutable data type, meaning its elements cannot be changed after creation.</li> <li>Attempting to modify tuple elements will result in a type error.</li> <li>An element of a tuple can be of a mutable type, such as a list.</li> <li>Modifying a list element within a tuple does not change the tuple itself.</li> <li>Tuples are faster to iterate than lists due to their immutable nature, making them ideal for data that does not change.</li> </ul> <p>======</p> <h5 id="102-tuple-operations">10.2 TUPLE OPERATIONS</h5> <ul> <li>A tuple is a ordered finite set of elements.</li> <li>Tuple operations include union, intersection, difference, and symmetric difference.</li> <li>The union of two tuples, denoted by $A \cup B$, is the set of elements that are in either tuple.</li> <li>The intersection of two tuples, denoted by $A \cap B$, is the set of elements that are in both tuples.</li> <li>The difference of two tuples, denoted by $A - B$, is the set of elements that are in tuple A but not in tuple B.</li> <li>The symmetric difference of two tuples, denoted by $A \oplus B$, is the set of elements that are in either tuple, but not in both.</li> </ul> <p>======</p> <h5 id="1021-concatenation">10.2.1 Concatenation</h5> <ul> <li>In Python, tuples can be joined using the concatenation operator (+).</li> <li>This is demonstrated by the concatenation of tuple1 and tuple2, resulting in a new tuple with combined elements.</li> <li>The concatenation operator can also be used to create a new tuple (tuple5) by combining tuple3 and tuple4.</li> <li>The concatenation operator can extend an existing tuple by creating a new tuple with the added elements.</li> <li>For example, a single element (6) or multiple elements (7,8,9) can be appended to tuple6 using the concatenation operator.</li> </ul> <p>======</p> <h5 id="1022-repetition">10.2.2 Repetition</h5> <ul> <li>Repetition operation in tuples is depicted by the symbol *.</li> <li>It is used to repeat elements of a tuple.</li> <li>The repetition operator requires the first operand to be a tuple.</li> <li>The second operand should be an integer only.</li> <li>Example: <code>tuple1 * 3</code> returns <code>('Hello', 'World', 'Hello', 'World', 'Hello', 'World')</code>.</li> </ul> <p>======</p> <h5 id="1023-membership">10.2.3 Membership</h5> <ul> <li>The ‘in’ operator checks if an element is present in a tuple and returns ‘True’ if it is, ‘False’ otherwise.</li> <li>The ’not in’ operator returns ‘True’ if an element is not present in a tuple, ‘False’ otherwise.</li> <li>Example using ‘in’: tuple1 = (‘Red’, ‘Green’, ‘Blue’); ‘Green’ in tuple1 returns ‘True’.</li> <li>Example using ’not in’: tuple1 = (‘Red’, ‘Green’, ‘Blue’); ‘Green’ not in tuple1 returns ‘False’.</li> <li>No equations or formulae are provided in the text.</li> </ul> <p>======</p> <h5 id="1024-slicing">10.2.4 Slicing</h5> <ul> <li>Slicing, similar to strings and lists, can be applied to tuples.</li> <li>The syntax for slicing a tuple is: tupleName[startIndex:stopIndex:stepSize].</li> <li>An empty start index implies slicing from the beginning, and an empty stop index implies slicing till the end of the tuple.</li> <li>A step size of 2 implies every second element is selected, starting from the first index.</li> <li>Negative indexing and step size of -1 can be used to reverse the order of elements in a tuple.</li> </ul> <p>======</p> <h5 id="103-tuple-methods-and-built-in-functions">10.3 Tuple Methods and Built-in Functions</h5> <ul> <li>The <code>len()</code> function returns the number of elements in a tuple.</li> <li>The <code>tuple()</code> function creates an empty tuple or a tuple from a sequence.</li> <li>The <code>count()</code> method returns the number of times a specified element appears in a tuple.</li> <li>The <code>index()</code> method returns the index of the first occurrence of the specified element in a tuple.</li> <li>The <code>sorted()</code> function returns a new sorted list from the elements of a tuple, but does not modify the original tuple.</li> <li>The <code>min()</code> and <code>max()</code> methods return the smallest and largest elements in a tuple, respectively.</li> <li>The <code>sum()</code> function returns the sum of all elements in a tuple.</li> </ul> <p>======</p> <h5 id="104-tuple-assignment">10.4 TUPLE ASSIGNMENT</h5> <ul> <li>Tuple assignment in Python is a feature that allows a tuple of variables on the left side of the assignment operator to be assigned respective values from a tuple on the right side.</li> <li>The number of variables on the left should match the number of elements in the tuple.</li> <li>If there is an expression on the right side, it is evaluated first, and then the result is assigned to the tuple.</li> <li>Example: (num1, num2) = (10, 20) will assign 10 to num1 and 20 to num2.</li> <li>If there are more variables on the left than elements in the tuple, a ValueError will be raised, as in (a, b, c, d) = (5, 6, 8).</li> </ul> <p>======</p> <h5 id="105-nested-tuples">10.5 NESTED TUPLES</h5> <ul> <li>A tuple inside another tuple is referred to as a nested tuple.</li> <li>This concept is demonstrated in Program 10-1, where roll number, name, and marks (in percentage) of students are stored in a tuple.</li> <li>To store details of multiple students, a nested tuple can be created.</li> <li>For example, <code>st=((101,"Aman",98),(102,"Geet",95),(103,"Sahil",87),(104,"Pawan",79))</code> represents a nested tuple.</li> <li>The nested tuple can be printed using a for loop, as shown in the program.</li> </ul> <p>======</p> <h5 id="106-tuple-handling">10.6 TUPLE HANDLING</h5> <ul> <li>Program 10-2 is a Python program that swaps two numbers without using a temporary variable, by using tuple assignment.</li> <li>Program 10-3 is a Python function that calculates the area and circumference of a circle, and returns them as a tuple.</li> <li>The area of the circle is calculated using the formula: area = πr², where r is the radius of the circle.</li> <li>The circumference of the circle is calculated using the formula: circumference = 2πr, where r is the radius of the circle.</li> <li>Program 10-4 is a Python program that inputs n numbers from the user, stores them in a tuple, and prints the maximum and minimum numbers from the tuple. The maximum and minimum numbers are calculated using the built-in max() and min() functions in Python.</li> </ul> <p>======</p> <h5 id="107-introduction-to-dictionaries">10.7 INTRODUCTION TO DICTIONARIES</h5> <ul> <li>Dictionaries are a data type in the mapping category.</li> <li>They consist of a set of keys and a set of values, with each key-value pair called an item.</li> <li>Keys and values are separated by a colon (:), and consecutive items are separated by commas.</li> <li>The items in dictionaries are unordered, meaning the data may not be returned in the same order as it was entered.</li> <li>A dictionary is created by enclosing a comma-separated list of key-value pairs in curly braces.</li> </ul> <p>======</p> <h5 id="1071-creating-a-dictionary">10.7.1 Creating a Dictionary</h5> <ul> <li>A dictionary is created by separating items with commas and enclosing them in curly braces. Each item is a key-value pair, separated by a colon.</li> <li>Keys in a dictionary must be unique and should be of any immutable datatype such as number, string, or tuple.</li> <li>Values can be repeated and can be of any data type.</li> <li>An empty dictionary can be created using curly braces or the built-in function <code>dict()</code>.</li> <li>Example: <code>dict1 = {}</code> or <code>dict2 = dict()</code> create an empty dictionary. <code>dict3 = {‘Mohan’:95,‘Ram’:89,‘Suhel’:92, ‘Sangeeta’:85}</code> creates a dictionary that maps names of students to their respective marks in percentage.</li> </ul> <p>======</p> <h5 id="1072-accessing-items-in-a-dictionary">10.7.2 Accessing Items in a Dictionary</h5> <ul> <li>The items in a dictionary are accessed using keys, not indices.</li> <li>Each key serves as an index and maps to a value.</li> <li>For example: <code>dict3 = {‘Mohan’:95,‘Ram’:89,‘Suhel’:92,‘Sangeeta’:85}</code> where ‘Ram’ always maps to 89 and ‘Sangeeta’ always maps to 85.</li> <li>The order of items in a dictionary does not matter.</li> <li>If a key is not present in the dictionary, attempting to access it will result in a KeyError.</li> </ul> <p>======</p> <h5 id="108-dictionaries-are-mutable">10.8 DICTIONARIES ARE MUTABLE</h5> <ul> <li>Dictionaries in Python are mutable data types.</li> <li>They can be modified after they have been created.</li> <li>This mutability allows for dynamic content changes.</li> <li>It is possible to add, update, or delete keys and values in a dictionary.</li> <li>This feature differentiates dictionaries from immutable data types, such as tuples and strings, in Python.</li> </ul> <p>======</p> <h5 id="1081-adding-a-new-item">10.8.1 Adding a new item</h5> <ul> <li>A new item can be added to a dictionary in Python by defining a new key and assigning a value to it.</li> <li>For example, if dict1 is a dictionary, the statement dict1[‘Meena’] = 78 adds the new item ‘Meena’: 78 to the dictionary.</li> <li>The updated dictionary contains all the previous items and the new item.</li> <li>The order of items in the dictionary is not important and can vary.</li> <li>No equations or formulae are provided in the text.</li> </ul> <p>======</p> <h5 id="1082-modifying-an-existing-item">10.8.2 Modifying an Existing Item</h5> <ul> <li>The existing dictionary can be modified by overwriting the key-value pair.</li> <li>For example, to modify a given item in the dictionary, dict1 = {‘Mohan’:95,‘Ram’:89,‘Suhel’:92, ‘Sangeeta’:85}#Marks of Suhel changed to 93.5.</li> <li>This can be done by dict1[‘Suhel’] = 93.5.</li> <li>After modification, the dictionary will be, dict1{‘Mohan’: 95, ‘Ram’: 89, ‘Suhel’: 93.5, ‘Sangeeta’: 85}.</li> <li>No equation or formula is provided in the text.</li> <li>Examples and their solutions are not included in the summary.</li> </ul> <p>======</p> <h5 id="109-dictionary-operations">10.9 DICTIONARY OPERATIONS</h5> <ul> <li>Dictionary operations are fundamental in Python and involve various methods to access, add, remove, and manipulate data in a dictionary.</li> <li>The syntax for creating a dictionary is: dict_name = {key:value, key:value, …}.</li> <li>To add an item to a dictionary, use the method dict_name[key] = value.</li> <li>To remove an item, use the method del dict_name[key].</li> <li>The methods dict_name.keys(), dict_name.values(), and dict_name.items() return the keys, values, and key-value pairs (tuples) in the dictionary, respectively.</li> <li>The .get() method can be used to access values in a more flexible way, allowing for a default value if the key is not found.</li> </ul> <p>======</p> <h5 id="1091-membership">10.9.1 Membership</h5> <ul> <li>The membership operator in Python checks if a key is present in a dictionary and returns True if it is, otherwise it returns False.</li> <li>This can be demonstrated with the ‘in’ keyword, such as ‘key’ in dictionary.</li> <li>The ’not in’ operator returns True if a key is not present in a dictionary and False otherwise.</li> <li>For example: dict1 = {‘Mohan’:95,‘Ram’:89,‘Suhel’:92, ‘Sangeeta’:85}, ‘Suhel’ in dict1 would return True.</li> <li>Similarly, dict1 = {‘Mohan’:95,‘Ram’:89,‘Suhel’:92, ‘Sangeeta’:85}, ‘Suhel’ not in dict1 would return False.</li> </ul> <p>======</p> <h5 id="1010-traversing-a-dictionary">10.10 TRAVERSING A DICTIONARY</h5> <ul> <li>In Python, dictionaries can be traversed using for loops to access each item.</li> <li>Method 1: Iterate through the keys of the dictionary using the ‘for key in dict1’ loop and print the corresponding values using dict1[key].</li> <li>Method 2: Iterate through both keys and values of the dictionary using the ‘for key, value in dict1.items()’ loop and print them directly.</li> <li>These methods provide a way to go through all the elements of a dictionary, which can be useful for various operations and manipulations.</li> </ul> <p>======</p> <h5 id="1011-dictionary-methods-and-built-in-functions">10.11 DICTIONARY METHODS AND BUILT-IN FUNCTIONS</h5> <ul> <li>The <code>len()</code> function returns the length or number of key-value pairs of the dictionary passed as an argument.</li> <li>The <code>dict()</code> function creates a dictionary from a sequence of key-value pairs.</li> <li>The <code>keys()</code>, <code>values()</code>, and <code>items()</code> methods return lists of keys, values, and tuples of key-value pairs in the dictionary, respectively.</li> <li>The <code>get()</code> method returns the value corresponding to the key passed as an argument. If the key is not present in the dictionary, it returns None.</li> <li>The <code>update()</code> method appends the key-value pairs of the dictionary passed as an argument to the key-value pairs of the given dictionary.</li> <li>The <code>del</code> keyword deletes the item with the given key from the dictionary. To delete the dictionary from memory, use <code>del Dict_name</code>.</li> <li>The <code>clear()</code> method deletes or clears all the items of the dictionary.</li> </ul> <p>======</p> <h5 id="1012-manipulating-dictionaries">10.12 MANIPULATING DICTIONARIES</h5> <ul> <li>Program 10-5 demonstrates manipulation of a dictionary ‘ODD’ containing odd numbers between 1 and 10. It shows how to display keys, values, items, find length, check for presence of a key, retrieve value, and delete an item.</li> <li>Program 10-6 is a program to enter names of employees and their salaries and store them in a dictionary. It creates an empty dictionary, takes input for number of employees, and populates the dictionary with name and salary inputs.</li> <li>Program 10-7 counts the number of times a character appears in a given string. It creates an empty dictionary, takes string input, and populates the dictionary with characters as keys and their counts as values.</li> <li>Program 10-8 converts a number entered by the user into its corresponding number in words. It defines a function ‘convert’ that takes a number as input, converts it to words, and returns the result. The program then takes number input, calls the function, and prints the number in words.</li> <li>Notably, all these programs use dictionary data structure to store, manipulate, and retrieve data.</li> </ul> <p>======</p>