Dictionary

Question 1

Printing key and values

Answer 1

dict = {'first' : 'sunday', 'second' :'monday', 'third' : 'tuesday'} 

dict.keys() method will print only the keys of the dictionary

for key in dict.keys():
    print(key)

dict.values() method will print only the values of the corressponding keys of the

dic for value in dict.values():
print(value)

Question 2

Update key value

Answer 2

dict = {'first' : 'sunday', 'second' : 'monday', 'third' : 'tuesday'}

for item in dict.items():
print(item) dict['fourth'] = 'wednesday'

for item in dict.items():
print(item)

Output:
(‘first’, ‘sunday’) (‘second’, ‘monday’) (‘third’, ‘tuesday’) (‘first’, ‘sunday’) (‘second’, ‘monday’) (‘third’, ‘tuesday’) (‘fourth’, ‘wednesday’)

Question 3

Delete key-value pair from dictionary

Answer 3

 dict = {'first' : 'sunday', 'second' : 'monday', 'third' : 'tuesday'} 
 for item in dict.items():
print(item) del dict['third']

removed_item = pop(item, “default message if not found”);

use del if you just want to remove an item and don’t need the removed value, and use pop() if you need the removed value or want to safely handle cases where the key might not exist in the dictionary.

Question 4

Merging 2 dictionaries

Answer 4

 dict1 = {'first' : 'sunday', 'second' : 'monday', 'third' : 'tuesday'} 
dict2 = {1: 3, 2: 4, 3: 5}
dict1.update(dict2)
print(dict1)

Output:
{‘first’: ‘sunday’, ‘second’: ‘monday’, ‘third’: ‘tuesday’, 1: 3, 2: 4, 3: 5}

Question 5

Dictionary

Answer 5

Mutable, Unordered data structure with key, value pair
names = {"non": "Nonna", "al": "Alan"}

Question 6

Keys

Answer 6

1. Unique
2. Can Be of Different Types: you can have a dictionary where some keys are strings, others are integers, and others are tuples.

3.Immutable: strings, numbers, or tuples.

4.Consistency is Key: recomended to keep them consistent and of the same type for readability and maintainability of your code.

Question 7

Check if key exists

Answer 7

if 'key1' in my_dict:
    print("Key1 exists")

Question 8

get(key, default=None):

Answer 8

Returns the value for the specified key if the key is in the dictionary. Otherwise, it returns None (or a specified default value).

print(my_dict.get('key1', 'Not Found'))

Question 8

Items

Answer 8

for key, value in my_dict.items():
    print(key, value)

Question 8

Clear

Answer 8

my_dict.clear()
removes all items from dict

Question 9

Update

Answer 9

Updates the dictionary with the key-value pairs from other, overwriting existing keys.
~~~
my_dict.update({‘key1’: ‘updated’, ‘key4’: ‘new value4’})
~~~

Question 9

pop(key, default)

Answer 9

Removes the specified key and returns the corresponding value. If the key is not found, default is returned if provided, otherwise a KeyError is raised.

print(my_dict.pop('key3', 'Not Found'))