Dictionary

Assertion (A): Dictionary is a collection of key-value pairs.

Reasoning (R): Each key in a dictionary maps to a corresponding value. Keys are unique and act as the index.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Dictionaries are enclosed within curly braces { }.

Reasoning (R): The key-value pairs are separated by commas (,).

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): The popitem() method can be used to delete elements from a dictionary.

Reasoning (R): The popitem() method deletes the last inserted key-value pair and returns the value of deleted element.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Keys of the dictionaries must be unique.

Reasoning (R): The keys of a dictionary can be accessed using values.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): clear() method removes all elements from the dictionary.

Reasoning (R): len() function cannot be used to find the length of a dictionary.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Items in dictionaries are unordered.

Reasoning (R): You may not get back the data in the same order in which you had entered the data initially in the dictionary.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Consider the code given below:

d={1: 'Amit', 2: 'Sumit', 5:'Kavita'}
d.pop(1) 
print(d) 

The output will be:

Amit #item is returned after deletion
{2: 'Sumit', 5: 'Kavita'}

Reasoning (R): pop() method not only deletes the item from the dictionary but also returns the deleted value.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Like lists, Dictionaries are mutable which means they can be changed.

A Python dictionary is a mapping of unique keys to values. It is a collection of key-value pairs.

The association of a key and a value is called a Key-Value pair.

To create a dictionary, key-value pairs are separated by comma.

In key-value pair, each key is separated from its value by a colon(:).

keys() function returns the keys of the dictionary.

Keys of a dictionary must be unique.

To delete an element, you can either use del statement or use pop() method.

The len() function returns total number of key-value pairs in a dictionary.

Accessing a value specified by a key, which is not in a dictionary using get() function, returns None.

Which of the statement(s) is/are correct?

1. In Python dictionary, the key-value pair is called an item.
2. Python dictionary is a mapping of unique keys to values.
3. Dictionary is mutable.
4. All of these.

To create an empty dictionary, we use the statement as:

1. d1 = {}
2. d1 = []
3. d1 = ()
4. d1 == {}

In a dictionary, the elements are accessed through:

1. key
2. value
3. label
4. None of these

Keys of a dictionary must be:

1. Similar
2. Unique
3. Both (i) and (ii)
4. All of these

To create a new dictionary with no items:

1. Dict
2. dict()
3. d1={}
4. Both 2 and 3

Which function is used to return a value for the given key?

1. len()
2. get()
3. keys()
4. None of these

Which function is used to remove all items from a particular dictionary?

1. clear()
2. pop()
3. delete()
4. rem()

What will be the output of the following Python code snippet?

d1 = { "amit" :40, "jatin" :45}
d2 = { "amit" :466, "jatin" :45}
d1 > d2

1. True
2. False
3. Error
4. None

Which of the following functions will return key-value pairs of the dictionary in the form of list of tuples?

1. key()
2. values()
3. items()
4. get()

Select the correct option to get the values of marks key:

Student={ "name" : "Emma", "class" :11, "sec": "a", "marks" :76}

1. Student.get(3)
2. Student.get("marks")
3. Student["marks"]
4. Both 2 and 3

Consider the given code:

D1={1: 'India', 2: 'Russia', 3: 'World'}
D2={'School' : 'EOIS' , 'Place ' : 'Moscow'}
print(D1.update (D2) )

What will be the output of the above code:

1. None
2. {1: 'India' , 2: 'Russia' , 3: 'World' , 'School' : 'EOIS' , 'Place' : 'Moscow'}
3. Error
4. None of these

What is a key-value pair in dictionary?

What are the differences between strings and dictionary?

Find errors and rewrite the same after correcting the following code:

d1 = {1:10, 2.5:20, 3:30, 4:40, 5:50, 6:60, 7:70}

Find errors and rewrite the same after correcting the following code:

d1(9) = 90 

Find errors and rewrite the same after correcting the following code:

del d1(2)  

Find errors and rewrite the same after correcting the following code:

pop d1[4]

Find errors and rewrite the same after correcting the following code:

d1.item()

Find errors and rewrite the same after correcting the following code:

d1.key()

Find errors and rewrite the same after correcting the following code:

d1.value()

Find errors and rewrite the same after correcting the following code:

d1.gets(4, 80) 

Find errors and rewrite the same after correcting the following code:

d1.len()

Find errors and rewrite the same after correcting the following code:

d1.clears()  

Suppose

>>> d1 = { 1 : 'one' , 2: 'two' , 3: 'three' , 4: 'four'}
>>> d2 = { 5 :'five', 6:'six' }

Write the output of the following code:

>>> d1.items() 
>>> d1.keys() 
>>> d1.values() 
>>> d1.update(d2)
>>> len(d1)

Suppose

>>> d1 = { 1 : 'one' , 2: 'two' , 3: 'three' , 4: 'four'}
>>> d2 = { 5 :'five', 6:'six' }

Write the output of the following code:

>>> del d1[3] 
>>> print(d1) 
>>> d1.pop(4) 
>>> print(d1) 
>>> d1 [8] =' eight'
>>> print(d1) 
>>> d1.clear() 
>>> print(d1)

Write a Python program to find the highest 2 values in a dictionary.

d = {'a': 10, 'b': 30, 'c': 20, 'd': 50, 'e': 40}
s = sorted(d.values())
print("Dictionary:", d)
print("Highest 2 values are:", s[-1], s[-2])

Dictionary: {'a': 10, 'b': 30, 'c': 20, 'd': 50, 'e': 40}
Highest 2 values are: 50 40

Write a Python program to input 'n' classes and names of their class teachers to store it in a dictionary and display the same. Also, accept a particular class from the user and display the name of the class teacher of that class.

n = int(input("Enter number of classes: "))
data = {}
for i in range(n):
    class_name = input("Enter class name: ")
    teacher_name = input("Enter teacher name: ")
    data[class_name] = teacher_name
print("Class data:", data)
find = input("Enter a class name to find its teacher: ")
if find in data:
    print("Teacher for class", find, "is", data[find])
else:
    print("Class not found in the data.")

Enter number of classes: 4
Enter class name: green
Enter teacher name: Aniket
Enter class name: yellow
Enter teacher name: Pratibha
Enter class name: red
Enter teacher name: Mayuri
Enter class name: blue
Enter teacher name: Prithvi
Class data: {'green': 'Aniket', 'yellow': 'Pratibha', 'red': 'Mayuri', 'blue': 'Prithvi'}
Enter a class name to find its teacher: red
Teacher for class red is Mayuri

Write a program to store students' names and their percentage in a dictionary, and delete a particular student name from the dictionary. Also display dictionary after deletion.

n = int(input("Enter number of students: "))
data = {}
for i in range(n):
    stu_name = input("Enter student name: ")
    percentage = input("Enter percentage: ")
    data[stu_name] = percentage
print("Student data:", data)
find = input("Enter a student name to delete: ")
if find in data:
    del data[find]
    print("Updated student data:", data)
else:
    print("Student not found in the data.")

Enter number of students: 4
Enter student name: Megha
Enter percentage: 98
Enter student name: Amit
Enter percentage: 88
Enter student name: Nitin
Enter percentage: 92
Enter student name: Amulya
Enter percentage: 79
Student data: {'Megha': '98', 'Amit': '88', 'Nitin': '92', 'Amulya': '79'}
Enter a student name to delete: Nitin
Updated student data: {'Megha': '98', 'Amit': '88', 'Amulya': '79'}

Write a Python program to input names of 'n' customers and their details like items bought, cost and phone number, store it in a dictionary and display all the details in a tabular form.

n = int(input("Enter the number of customers: "))
customer_data = {}

for i in range(n):
    name = input("Enter customer name: ")
    items_bought = input("Enter items bought: ")
    cost = float(input("Enter cost: "))
    phone_number = int(input("Enter phone number: "))

    customer_data[name] = {
        'Items Bought': items_bought,
        'Cost': cost,
        'Phone Number': phone_number
    }

print("Customer Details:")
print("Name\t\tItems Bought\t\tCost\t\tPhone Number")
for name, details in customer_data.items():
    print(name, "\t\t", details['Items Bought'], "\t\t", details['Cost'], "\t\t", details['Phone Number'])

Enter the number of customers: 4
Enter customer name: Sakshi
Enter items bought: Chocolate, Icecream
Enter cost: 200
Enter phone number: 9876354678
Enter customer name: Shashank
Enter items bought: Biscuits, Maggie, Soup
Enter cost: 450
Enter phone number: 8976346378
Enter customer name: Saanvi
Enter items bought: Veggies, Coffee
Enter cost: 300
Enter phone number: 8794653923
Enter customer name: Shivank
Enter items bought: Door mat, Bottles, Boxes
Enter cost: 600
Enter phone number: 6737486827
Customer Details:
Name            Items Bought            Cost            Phone Number
Sakshi           Chocolate, Icecream             200.0           9876354678
Shashank                 Biscuits, Maggie, Soup                  450.0           8976346378
Saanvi           Veggies, Coffee                 300.0           8794653923
Shivank                  Door mat, Bottles, Boxes                600.0           6737486827

What type of objects can be used as keys in dictionaries?

How will you check for a value inside a dictionary using in operator?

How is clear() function different from del statement?

The following code is giving some error. Find out the error and write the corrected code.

d1 = { "a" : 1, 1 : "a", [1, "a"] : "two"}

What will be the output of the following code?

d1 = {5: [6,7,8], "a": (1,2,3)} 
print (d1.keys () )
print (d1.values () )

Write the output of the following code:

d = { (1,2):1, (2,3):21 }
print (d[1,2] )

Write the output of the following code:

d = {'a':1, 'b':2, 'c':3}
print (d['a'])

Write a program to input your friends' names and their phone numbers and store them in a dictionary as the key-value pair. Perform the following operations on the dictionary:

(a) Display the Name and Phone numbers of all your friends.

(b) Add a new key-value pair in this dictionary and display the modified dictionary.

(c) Delete a particular friend from the dictionary.

(d) Modify the phone number of an existing friend.

(e) Check if a friend is present in the dictionary or not.

(f) Display the dictionary in sorted order of names.

phonebook = {}

num_friends = int(input("Enter how many friends: "))

for i in range(num_friends):
    name = input("Enter name of friend: ")
    phone = input("Enter phone number: ")
    phonebook[name] = phone

# (a) Display the Name and Phone numbers of all your friends.
print("Friends and their phone numbers:")
for name, number in phonebook.items():
    print(name + ": " + number)

# (b) Add a new key-value pair in this dictionary and display the modified dictionary.
new_name = input("\nEnter name of new friend: ")
new_number = input("Enter phone number of new friend: ")
phonebook[new_name] = new_number
print(phonebook)

# (c) Delete a particular friend from the dictionary.
del_name = input("\nEnter name of friend to delete: ")
if del_name in phonebook:
    del phonebook[del_name]
    print(del_name + " has been deleted.")
else:
    print(del_name + " not found.")
print(phonebook)

# (d) Modify the phone number of an existing friend.
mod_name = input("\nEnter name of friend to modify number: ")
if mod_name in phonebook:
    mod_number = input("Enter new phone number: ")
    phonebook[mod_name] = mod_number
    print(mod_name + "'s phone number has been modified.")
else:
    print(mod_name + " not found.")
print(phonebook)

# (e) Check if a friend is present in the dictionary or not.
check_name = input("\nEnter name of friend to check: ")
if check_name in phonebook:
    print(check_name + " is present in the dictionary.")
else:
    print(check_name + " is not present in the dictionary.")

# (f) Display the dictionary in sorted order of names.
sorted_keys = sorted(phonebook)
print("\nDictionary in sorted order of names:")
print("{", end = " ")
for key in sorted_keys:
    print(key, ":", phonebook[key], end = " ")
print("}")

Enter how many friends: 3
Enter name of friend: Mayuri
Enter phone number: 7689874888
Enter name of friend: Ankit
Enter phone number: 6748584757
Enter name of friend: Ashish
Enter phone number: 9088378388
Friends and their phone numbers:
Mayuri: 7689874888
Ankit: 6748584757
Ashish: 9088378388

Enter name of new friend: Sahini
Enter phone number of new friend: 8978909877
{'Mayuri': '7689874888', 'Ankit': '6748584757', 'Ashish': '9088378388', 'Sahini': '8978909877'}

Enter name of friend to delete: Mayuri
Mayuri has been deleted.
{'Ankit': '6748584757', 'Ashish': '9088378388', 'Sahini': '8978909877'}

Enter name of friend to modify number: Ankit
Enter new phone number: 8989587587
Ankit's phone number has been modified.
{'Ankit': '8989587587', 'Ashish': '9088378388', 'Sahini': '8978909877'}

Enter name of friend to check: Ashish
Ashish is present in the dictionary.

Dictionary in sorted order of names:
{ Ankit : 8989587587 Ashish : 9088378388 Sahini : 8978909877 }

Consider the following dictionary Prod_Price.

Prod_Price = {'LCD' : 25000,
                'Laptop' : 35000, 
                'Home Theatre' : 80000,
                'Microwave Oven' : 18000,
                'Electric Iron' : 2800,
                'Speaker' : 55000}

Find the output of the following statements:

(a) print(Prod_Price.get('Laptop'))

(b) print(Prod_Price.keys())

(c) print(Prod_Price.values())

(d) print(Prod_Price.items())

(e) print(len(Prod_Price))

(f) print('Speaker' in Prod_Price)

(g) print(Prod_Price.get('LCD'))

(h) del Prod_Price['Home Theatre']
     print (Prod_Price)

Write a program that prompts the user for product names and prices, and store these key-value pairs in a dictionary where names are the keys and prices are the values. Also, write a code to search for a product in a dictionary and display its price. If the product is not there in the dictionary, then display the relevant message.

prodDict = {}

n = int(input("Enter the number of products: "))

for i in range(n):
    name = input("Enter the name of product: ")
    price = float(input("Enter the price: "))
    prodDict[name] = price

print(prodDict)

pName = input("\nEnter product name to search: ")

if pName in prodDict:
    print("The price of", pName, "is: ", prodDict[pName])
else:
    print("Product", pName, " not found.")

Enter the number of products: 4
Enter the name of product: Television
Enter the price: 20000
Enter the name of product: Computer
Enter the price: 30000
Enter the name of product: Mobile
Enter the price: 50000
Enter the name of product: Air-Cooler
Enter the price: 35000
{'Television': 20000.0, 'Computer': 30000.0, 'Mobile': 50000.0, 'Air-Cooler': 35000.0}

Enter product name to search: Mobile
The price of Mobile is:  50000.0

Write a Python program that accepts a value and checks whether the inputted value is part of the given dictionary or not. If it is present, check for the frequency of its occurrence and print the corresponding key, otherwise print an error message.

d = {
    'A': 'apple',
    'B': 'banana',
    'C': 'apple',
    'D': 'orange',
    'E': 'strawberry'
}

v = input("Enter a value to check: ")
k = []

for key, value in d.items():
    if value == v:
        k.append(key)

if len(k) > 0:
    print("The value", v, "is present in the dictionary.")
    print("It occurs", len(k), "time(s) and is associated with the following key(s):", k)
else:
    print("The value", v, "is not present in the dictionary.")

Enter a value to check: apple
The value apple is present in the dictionary.
It occurs 2 time(s) and is associated with the following key(s): ['A', 'C']

An element in a dictionary is a combination of key-value pairs.

Internally, dictionaries are indexed on the basis of values.

We can repeat a key in dictionary.

In dictionary, two unique keys can have the same values.

clear() is used to delete a dictionary.

The key of a dictionary is a mutable data type.

List can be used as keys in a dictionary.

Updating an element in a dictionary at runtime is possible.

We can create immutable dictionaries in Python.