[python 기초] python의 dictionary에 대하여

Ditionary

---

{1:one, 2:two}

mapping: key값을 가지고 찾음!

1. 기본적인 사용 방법: {}

months = {1:'Jan', 2:'Feb', 3:'Mar', 4:'Apr', 5:'May', 6:'Jun',
          7:'Jul', 8:'Aug', 9:'Sep', 10:'Oct', 11:'Nov', 12:'Dec'}
 
print(months[1]) #Jan
 
items = [('name', 'May'), ('birth', 5)]
dict_items = dict(items)
print(dict_items) # {'name': 'May', 'birth': 5}
print(len(dict_items)) # 2
 
del dict_items['birth']
print(dict_items) # {'name': 'May'}
 
print('name' in dict_items) # True
print('birth' in dict_items) # False
 
# list_items = []
# list_items[42] = 'Jiyoung' # IndexError: list assignment index out of range
 
dict_items = {}
dict_items['name'] = 'Jiyoung'
print(dict_items) # {'name': 'Jiyoung'}

Dictionary 안에 또 Dictionary를 사용할수 있다!

people = {
    'Alice': {
        'phone': '010-1234',
        'email': 'Alice@mail.com'
    },
    'Beth': {
        'phone': '010-4321',
        'email': 'Beth@mail.com'
    }}
 
print(people) # {'Alice': 
              # {'phone': '010-1234', 'email': 'Alice@mail.com'}, 
              # 'Beth': 
              # {'phone': '010-4321', 'email': 'Beth@mail.com'}}
print(people['Alice']) # {'phone': '010-1234', 'email': 'Alice@mail.com'}
print(people['Alice']['phone']) # 010-1234

활용!

people = {
    'alice': {
        'phone': '010-1234',
        'email': 'Alice@mail.com'
    },
    'beth': {
        'phone': '010-4321',
        'email': 'Beth@mail.com'
    },
    'jiyoung': {
        'phone': '010-4200',
        'email': 'jiyoung@mail.com'
    }}
 
name = input('Name: ')
print('Are you looking for phone number or email?')
request = input('Phone number(p) or email(e)?: ')
 
if request == 'p': key ='phone'
if request == 'e': key ='email'
if name in people:
    print("{}'s {} is {}".format(name, key, people[name][key]))
else:
    print("We don't have {}'s information".format(name))
    
# Name: jiyoung
# Are you looking for phone number or email?
# Phone number(p) or email(e)?: e
# jiyoung's email is jiyoung@mail.com
 
# Phone number(p) or email(e)?: p
# jiyoung's phone is 010-4200
 
# Name: Babo
# Are you looking for phone number or email?
# Phone number(p) or email(e)?: p
# We don't have Babo's information

2. Dicionary method

1) Clear

people = {
    'alice': {
        'phone': '010-1234',
        'email': 'Alice@mail.com'
    },
    'beth': {
        'phone': '010-4321',
        'email': 'Beth@mail.com'
    },
    'jiyoung': {
        'phone': '010-4200',
        'email': 'jiyoung@mail.com'
    }}
 
print(people.clear()) # None

2) copy

x = {'username':'admin',
     'machines': ['foo', 'bar', 'baz']}
y = x.copy()
print(y) # {'username': 'admin', 'machines': ['foo', 'bar', 'baz']}
 
y['username'] = 'jiyoung'
print(x) # {'username': 'admin', 'machines': ['foo', 'bar', 'baz']}
print(y) # {'username': 'jiyoung', 'machines': ['foo', 'bar', 'baz']}

a = {}.fromkeys(['name', 'age'])
print(a) # {'name': None, 'age': None}
 
b = dict.fromkeys(['name', 'age'])
print(b) # {'name': None, 'age': None}
 
c = dict.fromkeys(['name', 'age'], 'Not yet')
print(c) # {'name': 'Not yet', 'age': 'Not yet'}

4) get (default = None)

d = {}
print(d.get('name')) # None
print(d.get('name', 'N/A')) # N/A
 
d['name'] = 'Jiyoung'
print(d.get('name')) # Jiyoung

활용하기

people = {
    'alice': {
        'phone': '010-1234',
        'email': 'Alice@mail.com'
    },
    'beth': {
        'phone': '010-4321',
        'email': 'Beth@mail.com'
    },
    'jiyoung': {
        'phone': '010-4200',
        'email': 'jiyoung@mail.com'
    }}
 
 
name = input('Name: ')
print('Are you looking for phone number or email?')
request = input('Phone number(p) or email(e)?: ')
 
if request == 'p': key ='phone'
if request == 'e': key ='email'
 
if name in people:
    print("{}'s {} is {}".format(name, key, people[name][key]))
else:
    print("{} is not in Book. Do you want save new one?".format(name))
    r = input('yes(y) or no(n)')
    if r == 'y':
        people[name] = {}
        new_phone = input("phone: ")
        people[name]['phone'] = new_phone
        new_email = input("email: ")
        people[name]['email'] = new_email
    if r == 'n': print('okay bye!')
 
print("you saved {}!".format(people[name]))

5) items(), keys(), values() (tuple로 가져옴)

d = {'title': 'python web site', 'url': 'www.python.org', 'spam': 0}
print(d.items()) # dict_items([('title', 'python web site'),
                 # ('url', 'www.python.org'), 
                 # ('spam', 0)])
print(d.keys()) # dict_keys(['title', 'url', 'spam'])
print(d.values()) # dict_values(['python web site', 'www.python.org', 0])

6) update()

d = {'title': 'python web site', 'url': 'www.python.org', 'spam': 0}
x = {'title': 'python'}
d.update(x)
print(d) # {'title': 'python', 'url': 'www.python.org', 'spam': 0}