All three are different type of data structures in python. This is used to store different Collections of data. Based on the usecase of our requirement, we need to choose among these.
Dictionary (dict):
Dictionary is collection of key value pair, where each key is associated with a value
Data can be retrieved based on key value(Key based search) as the keys are required to be unique.
Dictionaries are unordered till 3.7, values can be changed. Key name cannot be changed directly
Syntax:
inventory = {‘apple’:20, ‘Banana’:30 , ‘carrot’:15, ‘milk’:15}
print(‘t1. Inventory items’, inventory)
Dictionaries can be added with another value/modfied the value of existing key using the below syntax
inventory[‘egg’] = 20
inventory[‘bread’] = 25
print(‘t2. Updated Inventory items’, inventory)
inventory[‘egg’]= inventory[‘egg’]+5
print(‘t3. After restocking’, inventory)
removing the data from dict can be done using del keyword.
Checking the presence of data can be done using in keyword. Result will be boolean.
del inventory[‘carrot’]
del inventory[‘bread’]
print(‘t4. Updated Inventory after delete’, inventory)
is_bananas_in_inventory = ‘Banana’ in inventory
print(‘t5a. Is banana in inventory’, is_bananas_in_inventory)
is_oranges_in_inventory = ‘Orange’ in inventory
print(‘t5b. Is Orange in inventory’, is_oranges_in_inventory)
Notes:
Additionaly dict.items() will give each item in dictionary as tuple (like key value pair). by using list(dict.items()) we can also get the data as list. Using for loop and if condition, we can access particular key and do the desired operation for that data
print(‘tt6. Product:’, product, ‘count is:’, product_count)
print (‘t7. Iterating inventory gives tuple:’, inventory.items())
#Printing only egg count(Value of key ‘egg’) by itearting dict
for product, product_count in inventory.items():
if product is ‘egg’:
print(‘t8. Product:’, product, ‘ its count is:’, product_count)
#Printing egg count (value of key ‘egg’)
print(‘t9. Count of apple’,inventory[‘egg’])
1. Inventory items {‘apple’: 20, ‘Banana’: 30, ‘carrot’: 15, ‘milk’: 15}
2. Updated Inventory items {‘apple’: 20, ‘Banana’: 30, ‘carrot’: 15, ‘milk’: 15, ‘egg’: 20, ‘bread’: 25}
3. After restocking {‘apple’: 30, ‘Banana’: 30, ‘carrot’: 15, ‘milk’: 15, ‘egg’: 25, ‘bread’: 25}
4. Updated Inventory after delete {‘apple’: 30, ‘Banana’: 30, ‘milk’: 15, ‘egg’: 25}
5a. Is banana in inventory True
5b. Is Orange in inventory False
6. Product: apple count is: 30
6. Product: Banana count is: 30
6. Product: milk count is: 15
6. Product: egg count is: 25
7. Iterating inventory gives tuple: dict_items([(‘apple’, 30), (‘Banana’, 30), (‘milk’, 15), (‘egg’, 25)])
8. Product: egg its count is: 25
9. Count of apple 25
Set:
A set is an unordered collection of unique elements. Sets are mutable, but they do not allow duplicate elements.
Syntax:
botanical_garden = {‘rose’, ‘lotus’, ‘Lily’}
botanical_garden.add(‘Jasmine’)
botanical_garden.remove(‘Rose’)
is_present_Jasmine = ‘Jasmine’ in botanical_garden
Above we can see to define a set, adding a values and removing it. If we add same elements in a set, it will through an error.
Also we can compare two sets similar to venn diagram. Like Union, difference, intersection of two data sets.
rose_garden = {‘rose’, ‘lotus’, ‘Hybiscus’}
common_flower= botanical_garden.intersection(rose_garden)
flowers_only_in_bg = botanical_garden.difference(rose_garden)
flowers_in_both_set = botanical_garden.union(rose_garden)
Output will be a set by default.
If needed we can typecase into list using list(expression)
Tuple:
A tuple is an ordered collection of elements that is immutable, meaning it cannot be changed after it is created.
Syntax:
munnar_trip = (‘Munar’, ‘2024-06-06’, ‘Eravikulam National Park’)
germany_trip = (‘Germany’, ‘2025-1-1’, ‘Lueneburg’)
print(‘t1. Trip details’, ooty_trip, germany_trip)
#Accessing tuple using index
location = ooty_trip[0]
date = ooty_trip[1]
place = ooty_trip[2]
print(f’t2a. Location: {location} Date: {date} Place: {place} ‘)
location, date, place =germany_trip # Assinging a tuple to 3 different variables
print(f’t2b. Location: {location} Date: {date} Place: {place} ‘)
print(‘t3. The count of ooty_trip is ‘,ooty_trip.count)
Output:
1. Trip details (‘Ooty’, ‘2024-1-1’, ‘Botanical_Garden’) (‘Germany’, ‘2025-1-1’, ‘Lueneburg’)
2a. Location: Ooty Date: 2024-1-1 Place: Botanical_Garden
2b. Location: Germany Date: 2025-1-1 Place: Lueneburg
3. The count of ooty_trip is <built-in method count of tuple object at 0x0000011634B3DBC0>
Tuples can be accessed using index. The values of tuples can be assigned to multiple variables easily. We can combine two tuples which will create another tuple. But tuple cannot be modified.
