标签：font 重复 family lse 获取 使用 obb dict val
1. 字典的定义 dict{}
2. 字典特征：字典是无序的，key-value键值对形式，key值不重复
3. 字典的赋值：dictA = {keyA: valueA, keyB: valueB, keyC: valueC}
4. 字典的取值：dictA[keyA] dictA.get(keyA)
5. 字典的所有键：dictA.keys() key-value获取：dictA.items()
6. 修改字典中元素的值：dictA[keyA] = value
7. 获取字典的长度：len(dictA)
8. 字典中添加元素：dictA[key_new] = value
9. 删除字典所有元素：dictA.clear()
10. 删除整个字典：del dictA
11. 字典组合：dict(dictA, **dictB) dictA.update(dictB)
1. 字典的定义，字典的键名只能是数字、字符串、元组，且不能重复
stu1 = {"name": "Mr.逗", "sex": "male", "age": 20, "hobby": "run"}
print(stu1)
结果：
{‘sex‘: ‘male‘, ‘hobby‘: ‘run‘, ‘name‘: ‘Mr.逗‘, ‘age‘: 20}
2. 字典取值：dictA[keyA] dictA.get(keyA)
stu1 = {"name": "Mr.逗", "sex": "male", "age": 20, "hobby": "run"}
print(stu1["name"])
print(stu1.get("name"))
结果:
Mr.逗
Mr.逗
3. 修改字典值：dictA[keyA] = value，keyA是已存在的key
stu1 = {"name": "Mr.逗", "sex": "male", "age": 20, "hobby": "run"}
stu1["name"] = "Mr.小小逗"
print(stu1)
结果：
{‘hobby‘: ‘run‘, ‘age‘: 20, ‘name‘: ‘Mr.小小逗‘, ‘sex‘: ‘male‘}
4. 向字典中添加键值对，dictA[key_new] = value，key_new是不存在的
stu1 = {"name": "Mr.逗", "sex": "male", "age": 20, "hobby": "run"}
stu1["study"] = "python"
结果:
{‘age‘: 20, ‘study‘: ‘python‘, ‘name‘: ‘Mr.逗‘, ‘sex‘: ‘male‘, ‘hobby‘: ‘run‘}
5. 获取字典的长度：len(dictA)
stu1 = {"name": "Mr.逗", "sex": "male", "age": 20, "hobby": "run"}
print(len(stu1))
结果:
4
6. 两个字典的组合：dictA.update(dictB) dict(dictA, **dictB)
B = {"name": "xiaojian", "age": 28, "is_marry": False}
B.update({"role": "teacher", "class": "python"})
print(B)
结果:
{‘class‘: ‘python‘, ‘is_marry‘: False, ‘age‘: 28, ‘role‘: ‘teacher‘, ‘name‘: ‘xiaojian‘}
B = {"name": "xiaojian", "age": 28, "is_marry": False}
C = {"role": "teacher", "class": "python"}
D = dict(B, **C)
print(D)
结果:
{‘class‘: ‘python‘, ‘is_marry‘: False, ‘age‘: 28, ‘role‘: ‘teacher‘, ‘name‘: ‘xiaojian‘}
7. 删除字典中所有元素：dictA.clear()，只是清空字典
a = {"name": "Jack", "sex": "M"}
a.clear()
print(a)
结果:
{}
8. 删除整个字典：del dictA
a = {"name": "Jack", "sex": "M"}
del a
print(a)
结果:
Traceback (most recent call last):
File "<pyshell#5>", line 1, in <module>
print(a)
NameError: name ‘a‘ is not defined
标签：font 重复 family lse 获取 使用 obb dict val
原文地址：https://www.cnblogs.com/cnhkzyy/p/9065919.html
