# examples for Dictionaries

# creating a dictionary
phonebook = {'upsorn': '111-1111', 'Chris':'222-2222', 'Tom':'333-3333'}
print(phonebook)


# accessing / retrieving an item from a dictionary
print('phonebook[\'Tom\'] =', phonebook['Tom'])


# adding items to an existing dictionary
phonebook = {'upsorn': '111-1111', 'Chris':'222-2222', 'Tom':'333-3333'}
phonebook['Joe'] = '444-4444'
print('add \'Joe\', phonebook =', phonebook)


# deleting items from a dictionary
del phonebook['Chris']
print('delete \'Chris\', phonebook =', phonebook)

# pop()
phone_number = phonebook.pop('upsorn') # return the value associated with a specified key
print('pop(\'upsorn\') =', phone_number, ', phonebook =', phonebook)
print('randomly selected with popitem():' + str(phonebook.popitem())) # remove and return a randomly selected key-value pair
print('phonebook =', phonebook)

# length of dictionaries
num_items = len(phonebook)
print('len(phonebook) =', num_items, ', phonebook =', phonebook)


# let's re-assign our phonebook before trying other examples
phonebook = {'upsorn': '111-1111', 'Chris':'222-2222', 'Tom':'333-3333'}
print('re-assign phonebook =,', phonebook)

# retrieve a value for a particular key
print('phonebook[\'Tom\'] =', phonebook['Tom'])
print('phonebook.get(\'Tom\') =', phonebook.get('Tom'))

# print(phonebook['Tim'])  # - Throws a KeyError exception since it's not there!

# no default value, a non-existent key results in "None"
print('access a non-existent key, phonebook.get(\'Tim\') =',
      phonebook.get('Tim'))

# set default value, a non-existent key results in a default value
print('access a non-existent key, phonebook.get(\'Tim\', \'Key not in phonebook\') =',
      phonebook.get('Tim', 'Key not in phonebook'))

# retrieve all the keys and values
print('phonebook.items() =', phonebook.items())

# retrieve all the available keys
print('phonebook.keys() =', phonebook.keys())

# retrieve all the values
print('phonebook.values() =', phonebook.values())


# in
print('check if \'Tom\' in phonebook =', 'Tom' in phonebook)
print('check if \'Tom\' not in phonebook =', 'Tom' not in phonebook)
print('check if \'Tom\' in phonebook.keys() =', 'Tom' in phonebook.keys())
print('check if \'333-3333\' in phonebook.values() =', '333-3333' in phonebook.values())


# empty the dictionary
phonebook.clear()
print('clear phonebook =', phonebook)

print('-----------------')

# mix data types in a dictionary
test_scores = {'Tom' : [88, 92, 100],
               'John' : [95, 88, 81],
               'Ethan' : [70, 75, 78]}
print('mix data type, test_scores =', test_scores)
print('John\'s scores : ', test_scores['John'])
Ethan_scores = test_scores['Ethan']
print('Ethan\'s scores : ' + str(Ethan_scores))   # notice: why do we need str()?

print('-----------------')

# wrap up
dict = {}
dict[1] = 'cat'
dict['dog'] = -8
dict[False] = 'squirrel'

print(dict.keys())
print(dict.values())
print(dict)

if 'dog' in dict.keys():
    print('dog has a mapping!')
if 'cat' in dict.keys():
    print('cat has a mapping!')

dict['dog'] = 5
print(dict)


print("==== let's do an exercise ====")
# exercise
experience = {}
more_input = 'Y'
# You can do input validation to check if more_input is entered properly.
# However, let's skip that for now.
while more_input == 'Y' or  more_input == 'y':
    name_of_experience = input('Enter name of experience : ')
    company = input('Enter company : ')
    year = input('Enter year : ') # let's make this a string
    experience[year] = [name_of_experience, company]
    #print(experience)
    more_input = input('Do you want to enter more experience ? (Y/N) :')

print(experience)

# What happens if a user enters
# 'software engineer', 'IBM', '1996'
# 'manager', 'Target', '1996'

print("==== example for k in dict ====")
for k in experience:
    print(k)

print("==== example for k in dict.keys() ====")
for k in experience.keys():
    print(k)

print("==== example for v in dict.values() ====")
for v in experience.values():
    print(v)

print("==== example for k,v in dict.items() ====")
for k,v in experience.items():
    print(k, v)