Python tuple & Dictionary

​Tuple
range
dictionary
set

Multiple Choice

What is the output of the following code?

my_tuple = (1, 2, 3)

print(my_tuple[1])

• 1

• 2

• 3

• Error

Multiple Choice

How can you create a tuple with a single element?

• single_element_tuple = (5,)

• single_element_tuple = {5}

• single_element_tuple = [5]

• single_element_tuple = (5)
  

Multiple Choice

Which of the following is a correct way to create a tuple in Python?

• my_tuple = [1, 2, 3]

• my_tuple = {1, 2, 3}

• my_tuple = (1, 2, 3)

• my_tuple = 1, 2, 3

​tuple:
~are used to store multiple items in a single variable
~items are ordered and unchangeable/immutable
~ are written with round brackets-parenthesis ( ).

Tuple items:
~ items are ordered, unchangeable, and allow duplicate values.

~ items can be of any data type

~zero based items

​Tuple item Indexing:
Positive(+ve)
~left to right
~zero based index

Negative (-ve)
~right to left
~starts from -1

​Access Tuple Items:
We can access tuple items by referring to its index, inside square brackets [].

Tuple length function:
~to find out the number of tuple items
~use len() function

Tuple with one item:
~We have to add a comma after the item, otherwise Python will not recognize it as a tuple.

Join Items of tuples:
To join two or more tuples we can use the + operator

Tuple methods:
~we can use to manipulate on tuples items:

1.count()
Returns the number of times a specified value occurs in a tuple..

2. index()
   returns the position or index of the specified value
   

3. len()
   used to determine the length or the number of elements in a tuple
   

4. sum()
   Return the sum of all elements in the tuple

   
   
   

5. max()
   used to find the maximum value occurs in a tuple.
   

6. min()
   used to find the minimum value occurs in a tuple.
   

Activities:

Create a Python program to create a tuple named book_info to store information about english novel ‘The Giver’. Include attributes such as title, author, and year of publication. Assign appropriate values and print the tuple.

Write a Python program to receive user input for User_ID and password. Validate the provided User_ID and password against predefined values stored in a tuple. If both conditions are true, display the message "Welcome to your page"; otherwise, show the message "Sorry, you entered incorrect User_ID and Password."

​range function()
is used to generate a sequence of numbers. It’s very commonly used in loops.

Multiple Choice

What is the output of the following code?

for i in range(3):

print(i)

• 1 2 3

• 0 1 2

• 0 1 2 3

• Error

Multiple Choice

What does range(5, 15, 3) do?

• Generates numbers 5 through 15, stepping by 3

• Generates numbers 5, 8, 11, 14

• Generates numbers 5, 8, 11

• Generates numbers 5, 10, 15

​range() function:
returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and stops before a specified number

It is commonly used in for loops to generate a series of numbers.

Syntax:

range(Start, Stop, step)
 

x=range(1,10,2) for n in x: print(n)#indentation

​Using starting and ending:

to create a sequence of numbers from 3 to 5, and print each item in the sequence

Example:
x=range(3,5)
for n in x:
print(n)

output????

​Using starting, ending, increment:

to create a sequence of numbers from 3 to 11, but increment by 2 instead of 1:

Example:
x=range(3,11,2)
for n in x:
print(n)

output????

​start (optional) - starting value; the default value is 0.

stop (required) - ending number; this number is not included in the sequence; 

step (optional) - increment value; the default value is 1

Multiple Choice

Which of the following is the correct way to define a dictionary in Python?

• my_dict = {"name": "John", "age": 25}

• my_dict = [("name", "John"), ("age", 25)]

• my_dict = "name": "John", "age": 25

• my_dict = ("name", "John", "age", 25)

Multiple Choice

What will the following code output?

my_dict = {"name": "John", "age": 25}

print(my_dict.get("age"))

• "age"

• 25

• KeyError

• None

Dictionary
my_dictionary={
"name": "Sonam",
"my_class":10
}

​Python Dictionary

​Dictionary:
~are used to store data values in key:value pairs.

~is a collection which is ordered, changeable and do not allow duplicates

~Dictionaries are written with curly brackets, and have keys and values { }

~Each key is separated from its value by a colon (:), the items are separated by commas..

x={
"School":"UA","Estd Year":"2002"
}
print(x.keys()

Example:

dict={'Name': 'Jigdrel',

'Sex':'Male',

'Age':'15'}

print(dict)

​Accessing items:
~We can access the items of a dictionary by referring to its key name, inside square brackets..
~We can also use get() method....

Open Ended

Write a  Python program that acts as personal digital assistant, storing name, class and roll number of a student.

name - Karma, class- X, roll_number- 5

​Dictionary Methods

Python has a set of built-in methods that can use on dictionaries.

1. clear()
Removes all the elements from the dictionary

2. copy()
   Returns a copy of the dictionary.
   
   

​3. get()
Returns the value of the specified key.

4. pop()

Removes the element with the specified key.

​5. items()
The view object contains the key-value pairs of the dictionary, as tuples in a list..

6. keys()

Returns a list containing the dictionary's keys.

6. values()

Returns a list of all the values in the dictionary.

​Change values:
We can change the value of a specific item by referring to its key name

Add items:
adds new items to an existing items
is done using new index key and assigning a value to it

update()
Updates the dictionary with the specified key-value pairs.

Activities: 2023 BCSE trial

One of the shops in Thimphu wants to display the items they have in stock and their cost

prices. The shop also wants to display the total cost price of all the items as shown below.

Therefore, the shop owner has requested you to write a Python program with the following

criteria:

i. Use a dictionary to store item lists and their cost as keys and values respectively

ii. Display the dictionary using a for loop

iii. Add the values from the dictionary and display as given in the output with the same format.

​Set:

set
is an unordered collection of unique items. Sets cannot have duplicate values and their values can be changed (Mutable).

It is defined using curly braces {} or the built-in set() function and the elements are separated by commas.

​Set Methods
Python has a set of built-in methods that you can use on sets. Here are some of the common dictionary methods in Python:

​copy()
Returns a copy of the set

add()
Adds an element to the set

discard()
Remove the specified item

clear()
Removes all the elements from the set

difference ()
Returns a set containing the difference between two or more sets

intersection ()
Return a set that contains the items that exist in both set x, and set y

Output?????

union()
Return a new set containing all common elements from both sets without duplicates.

issubset()

Returns True if another set contains this set

issuperset()

checks whether the set contains all the elements of another set.

​isdisjoint():
Returns True if two sets have no elements in common