Dictionary

d = {'x': 10, 'y': 20}
print(type(d))  # <class 'dict'>

print(d['x'])  # 10
d['x'] = 100
print(d)  # {'x': 100, 'y': 20}
d['z'] = 'ZZZ'
print(d)  # {'x': 100, 'y': 20, 'z': 'ZZZ'}
d[1] = 10000
print(d)  # {'x': 100, 'y': 20, 'z': 'ZZZ', 1: 10000}

print(dict(a=10, b=20))  # {'a': 10, 'b': 20}, 사전 생성의 또다른 방법

####################################################################
d = {'x': 10, 'y': 20}
print(help(dict))

print(d.keys())  # dict_keys(['x', 'y'])
print(d.values())  # dict_values([10, 20])

d2 = {'x': 1000, 'j': 500}
d.update(d2)
print(d)  # {'x': 1000, 'y': 20, 'j': 500}

d1 = {'a': 1}
d2 = {'b': 2}
d3 = d1 | d2
print(d3)  # {'a': 1, 'b': 2}

# d['z']  # KeyError: 'z'
r = d.get('z')
print(r)  # None
print(type(r))  # <class 'NoneType'>
rr = d.get('z', 0)

print(d)  # 'x': 1000, 'y': 20, 'j': 500}
d.pop('x')  # 1000
print(d)  # {'y': 20, 'j': 500}
del d['y']
print(d)  # {'j': 500}

d = {'x': 10, 'y': 20}
d.clear()
print(d)  # {}
exist = 'a' in d
print(exist)  # False

####################################################################
x = {'a': 1}
y = x
y['a'] = 1000
print(x)  # {'a': 1000}
print(y)  # {'a': 1000}

x = {'a': 1}
y = x.copy()
y['a'] = 1000
print(x)  # {'a': 1}
print(y)  # {'a': 1000}