Tips python dictionary

　　　　　　　　　　　　　　　　　　Dictionary little knowledge 
dic = { "name": "tom", "Age": 23, ". Price": 110} 
# 01 : extract key

　　

print("1>>", dic["name"],type(dic["name"]))  # 1>> tom    <class 'str'>
print("2>>", dic.get("name"))  # 1>> tom
print("3>>", dic.get("n"),type(dic.get("n")))  # 3>> None   <class 'NoneType'>

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# 02: Evaluating key or value exists

　　

1 print('name' in dic)   #True
2 print('tom' in dic)   #False
3 print('n' in dic)   #False

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# 03 : Setting the value of the specified field

　　

dic['name']="jack"
print(dic)  #{'name': 'jack', 'age': 23, 'price': 110}
print(dic['name'])  # jack

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# 04: access to all the keys and values

 

　　

# 1:提取所有的键
print(dic.keys())  # dict_keys(['name', 'age', 'price'])
print(type(dic.keys()))  # <class 'dict_keys'>

# 2：提取所有的值
print(dic.values())  # dict_values(['tom', 23, 110])
print(type(dic.values()))  # <class 'dict_values'>

for key, value in dic.items():
    print(">>", key, value)

>> name tom
>> age 23
>> price 110

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