notes

dictionary

import os

os.system('clear')

print('Dictionaries:')
dict = {'name':'Robbie', 'age':44, 'courses':['math','comp-sci']}

print(dict) # {'name':'Robbie', 'age':44, 'courses':['math','comp-sci']}
print(dict['name']) # Robbie
print(dict['courses']) # ['math','comp-sci']

print(dict.get('age')) # 44

# by using the method get when a key that not exist will return none or the second argument instead of exception 
# get(key, default value)
print(dict.get('phone', 'Key not found'))

# adding key / value 
dict['phone'] = '555-555-5555'

# changing value
dict['age'] = 45
print(dict) # {'name': 'Robbie', 'age': 45, 'courses': ['math', 'comp-sci'], 'phone': '555-555-5555'}

# update method
dict.update({'name':'Cathy','age':33, 'email':'cathy@gmail.com','courses':['math','poli-sci']})
print(dict)

# deleting using del
del dict['age']
print(dict) # {'name': 'Cathy', 'courses': ['math', 'poli-sci'], 'phone': '555-555-5555', 'email': 'cathy@gmail.com'}

# getting the value from the key and deleting the key-value pair
email = dict.pop('email')
print(email) # cathy@gmail.com
print(dict) # {'name': 'Cathy', 'courses': ['math', 'poli-sci'], 'phone': '555-555-5555'}

print(len(dict)) # 3
print(dict.keys()) # dict_keys(['name', 'courses', 'phone'])
print(dict.values()) # dict_values(['Cathy', ['math', 'poli-sci'], '555-555-5555'])
print(dict.items()) # dict_items([('name', 'Cathy'), ('courses', ['math', 'poli-sci']), ('phone', '555-555-5555')])

for key, value in dict.items():
    print(key, value) 
    
# name Cathy
# courses ['math', 'poli-sci']
# phone 555-555-5555