Lesson 025: Dictionary: after class test questions and answers when the index is not easy to use

Test questions ：

0. When you hear your friends talking about “ mapping ”、“ Hash ”、“ hash ” perhaps “ Relational arrays ” When , In fact, what are they talking about ？

answer ： Yes , As a matter of fact, they are discussing our introduction “ Dictionaries ”, It's all a concept ！（ Bear in mind , loading X The essence of is to say the same thing as different things ~）

1. Try putting the data （‘F’: 70, ‘C’: 67, ‘h’: 104, ‘i’: 105, ‘s’: 115） Create as a dictionary and access key ‘C’ Corresponding value ？

>>> MyDict = dict((('F', 70), ('i',105), ('s',115), ('h',104), ('C',67)))
>>> MyDict_2 = {
    'F':70, 'i':105, 's':115, 'h':104, 'C':67}
>>> type(MyDict)
<class 'dict'>
>>> type(MyDict_2)
<class 'dict'>
>>> MyDict['C']
67

2. In square brackets （“[]”） The enclosed data is called a list , Then use braces （“{}”） The enclosed data is called dictionary , Am I right? ？

answer ： incorrect .

>>> NotADict = {
    1, 2, 3, 4, 5}
>>> type(NotADict)
<class 'set'>

3. How do you understand that there are some things a dictionary can do , but “ Omnipotent ” Lists are hard to implement （ I can't do it T_T）？

>>> brand = [' Lining ', ' Nike ', ' Adidas ', ' fish C Studio ']
>>> slogan = [' Anything is possible ', 'Just do it', 'Impossible is nothing', ' Let programming change the world ']
>>> print(' fish C The slogan of the studio is ：', slogan[brand.index(' fish C Studio ')])
 fish C The slogan of the studio is ：  Let programming change the world 

>>> dict1 = {
    ' Lining ':' Anything is possible ', ' Nike ':'Just do it', ' Adidas ':'Impossible is nothing', ' fish C Studio ':' Let programming change the world '}
>>> print(' fish C The slogan of the studio is ：', dict1[' fish C Studio '])
 fish C The slogan of the studio is ：  Let programming change the world 

4. The following code , Are they all doing the same thing ？ Can you see the difference ？

>>> a = dict(one=1, two=2, three=3)
>>> b = {
    'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({
    'three': 3, 'one': 1, 'two': 2})

answer ： Yes , They are all creating dictionaries ：a = dict(one=1, two=2, three=3), Uh , I can't see the difference ~

5. Pictured , Can you guess the code with the mosaic part ？

data = "1000, Little turtle , male "
MyDict = {
    }
#  Remember how to split strings , Don't forget after learning ^_^
(MyDict['id'], MyDict['name'], MyDict['sex']) = data.split(',') 

print("ID: " + MyDict['id'])
print("Name: " + MyDict['name'])
print("Sex " + MyDict['sex'])

use one's hands ：

0. Try to use the characteristics of the dictionary to write an address book program , The function is shown in the figure ：

print('|---  Welcome to the address book program  ---|')
print('|--- 1： Query contact information  ---|')
print('|--- 2： Insert a new contact  ---|')
print('|--- 3： Delete existing contacts  ---|')
print('|--- 4： Quit the address book program  ---|')

contacts = dict()

while 1:
    instr = int(input('\n Please input the relevant instruction code ：'))
    
    if instr == 1:
        name = input(' Please enter the contact name ：')
        if name in contacts:
            print(name + ' : ' + contacts[name])
        else:
            print(' The name you entered is no longer in the address book ！')

    if instr == 2:
        name = input(' Please enter the contact name ：')
        if name in contacts:
            print(' The name you entered already exists in the address book  -->> ', end='')
            print(name + ' : ' + contacts[name])
            if input(' Whether to modify user profile （YES/NO）：') == 'YES':
                contacts[name] = input(' Please enter the user's contact number ：')
        else:
            contacts[name] = input(' Please enter the user's contact number ：')

    if instr == 3:
        name = input(' Please enter the contact name ：')
        if name in contacts:
            del(contacts[name])         #  You can also use dict.pop()
        else:
            print(' The contact you entered does not exist .')
            
    if instr == 4:
        break

print('|---  Thank you for using the address book program  ---|')