Python内置函数locals()和vars()以及globals()的使用

locals()

代码实验:

# locals()函数使用示例

result = locals()
print("nn变量创建前...")
print("变量类型:", type(result), "变量长度:",len(result))
print(result)
#---------------------------------#
aString = "abc"
bInt = 22
cFloat = 3.14
dList = [0, 1, 2, 3]
print("nn变量创建后...")
result = locals()
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

控制台结果输出:

Windows PowerShell
版权所有 (C) Microsoft Corporation。保留所有权利。

尝试新的跨平台 PowerShell https://aka.ms/pscore6

加载个人及系统配置文件用了 750 毫秒。
(base) PS C:UserschenxuqiDesktopnewstest>  & 'D:Python37python.exe' 'c:Userschenxuqi.vscodeextensionsms-python.python-2021.10.1336267007pythonFileslibpythondebugpylauncher' '11445' '--' 'c:UserschenxuqiDesktopnewstesttest_01.py'


变量创建前...
变量类型:  变量长度: 10
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000001CAECD5F048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_01.py', '__cached__': 
None, 'result': {...}}


变量创建后...
变量类型:  变量长度: 14
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000001CAECD5F048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_01.py', '__cached__': 
None, 'result': {...}, 'aString': 'abc', 'bInt': 22, 'cFloat': 3.14, 'dList': [0, 1, 2, 3]}
(base) PS C:UserschenxuqiDesktopnewstest> 

globals()
代码实验:

# 测试globals()函数
print("nn变量创建前...")
result = globals()
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

# --------------------------------- #

globals()["age"] = 22
print("通过globals函数创建变量age, age =", age) 


globals()["age"] = '二十二岁'
print("通过globals函数修改变量age, age =", age) 
AGE = 33
print("AGE =", AGE) 
globals()["AGE"] = '八十八岁'
print("通过globals函数修改变量AGE, AGE =", AGE) 
# --------------------------------- #

aString = "abc"
bInt = 22
cFloat = 3.14
dList = [0, 1, 2, 3]
print("nn变量创建后...")
# result = globals()
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

控制台结果输出:

Windows PowerShell
版权所有 (C) Microsoft Corporation。保留所有权利。

尝试新的跨平台 PowerShell https://aka.ms/pscore6

加载个人及系统配置文件用了 736 毫秒。
(base) PS C:UserschenxuqiDesktopnewstest>  & 'D:Python37python.exe' 'c:Userschenxuqi.vscodeextensionsms-python.python-2021.10.1336267007pythonFileslibpythondebugpylauncher' '14902' '--' 'c:UserschenxuqiDesktopnewstesttest_02.py'


变量创建前...
变量类型:  变量长度: 10
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002385D43F048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_02.py', '__cached__': None, 'result': {...}}
通过globals函数创建变量age, age = 22
通过globals函数修改变量age, age = 二十二岁
AGE = 33
通过globals函数修改变量AGE, AGE = 八十八岁


变量创建后...
变量类型:  变量长度: 16
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002385D43F048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_02.py', '__cached__': None, 'result': {...}, 'age': '二十二岁', 'AGE': '八十八岁', 'aString': 'abc', 'bInt': 22, 'cFloat': 3.14, 'dList': [0, 1, 2, 3]}
(base) PS C:UserschenxuqiDesktopnewstest>

vars([object])

实验代码展示:

# 测试vars()函数

print("变量长度:",len(vars()))
print(vars())

print('类定义之前'.center(50,'-'))
result = vars()
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

# ----------------------------------------------------------- #
class Person():
  '''定义基类Person'''
  def __init__(self, name, age):
    '''初始化属性name和age'''
    self.name = name
    self.age = age
  def printInfo(self):
    print(
      '---我是一个实例对象, 属于类型:{0:^35}   ---我的名字是: {1:{3}<8}   ---我的年龄是: {2:<5}'.format(
        str(self.__class__), str(self.name), str(self.age), chr(12288)
      )
    )

class Student(Person):  
  '''定义基类Person的子类Student'''
  def __init__(self, name, age, grade):
    '''初始化父类的属性name和age'''
    super().__init__(name, age)
    self.grade = grade
  def printInfo(self):
    print(
      '---我是一个实例对象, 属于类型:{0:^35}   ---我的名字是: {1:{3}<8}   ---我的年龄是: {2:<5}'.format(
        str(self.__class__), str(self.name), str(self.age), chr(12288)
      )
    )


# result = vars()
print('类定义之后'.center(50,'-'))
print("变量类型:", type(result), "变量长度:",len(result))
print(result)
# ----------------------------------------------------------- #

per = Person('人物', 18)
stu = Student("学生", 22, '二年级-sophomore')

print('实例对象创建之后'.center(50,'-'))
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

print()
print('实例对象创建之后'.center(50,'-'))

print('实例对象per的属性名与属性值'.center(50,'-'))
result = vars(per)
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

print()
print('实例对象stu的属性名与属性值'.center(50,'-'))
result = vars(stu)
print("变量类型:", type(result), "变量长度:",len(result))
print(result)

控制台结果输出:

Windows PowerShell
版权所有 (C) Microsoft Corporation。保留所有权利。

尝试新的跨平台 PowerShell https://aka.ms/pscore6

加载个人及系统配置文件用了 730 毫秒。
(base) PS C:UserschenxuqiDesktopnewstest>  & 'D:Python37python.exe' 'c:Userschenxuqi.vscodeextensionsms-python.python-2021.10.1365161279pythonFileslibpythondebugpylauncher' '5753' '--' 'c:UserschenxuqiDesktopnewstesttest_03.py'
变量长度: 9
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002091CDDF048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_03.py', '__cached__': None}
----------------------类定义之前-----------------------
变量类型:  变量长度: 10
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002091CDDF048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_03.py', '__cached__': None, 'result': {...}}
----------------------类定义之后-----------------------
变量类型:  变量长度: 12
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002091CDDF048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_03.py', '__cached__': None, 'result': {...}, 'Person': , 'Student': }
---------------------实例对象创建之后---------------------
变量类型:  变量长度: 14
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x000002091CDDF048>, '__spec__': None, '__annotations__': {}, '__builtins__': , '__file__': 'c:\Users\chenxuqi\Desktop\news\test\test_03.py', '__cached__': None, 'result': {...}, 'Person': , 'Student': , 'per': <__main__.Person object at 0x000002091D02E148>, 'stu': <__main__.Student object at 0x000002091D02E0C8>}

---------------------实例对象创建之后---------------------
-----------------实例对象per的属性名与属性值------------------
变量类型:  变量长度: 2
{'name': '人物', 'age': 18}

-----------------实例对象stu的属性名与属性值------------------
变量类型:  变量长度: 3
{'name': '学生', 'age': 22, 'grade': '二年级-sophomore'}
(base) PS C:UserschenxuqiDesktopnewstest>