字符串→变量名

eval 执行表达式

exec 执行语句

字符串←变量名

globals 全局变量

locals 局部变量

vars 类的成员

例子

i = 0
exec('j = 0')
print(globals())

{'__name__': '__main__',
 ...
 'i': 0,
 'j': 0}

class Dummy(object):
    def __init__(self) -> None:
        self.i = 0
        exec('self.j = 0')

dummy = Dummy()
print(vars(dummy))

{'i': 0, 'j': 0}

应用

class EasyArgs(object):
    def __init__(self, **kvps):
        self.add(**kvps)
    def add(self, **kvps):           # 函数参数名转化成字符串(字典的键)
        for k,v in kvps.items():
            exec(f'self.{k} = None') # 字符串转化成示例的成员变量名
            vars(self)[k] = v

if __name__ == '__main__':
    args = EasyArgs(batch_size = 32)
    args.add(epochs = 64)
    print(vars(args))                # 成员变量名转化成字符串
    print(args.batch_size)           # 直接根据成员变量名使用变量
    print(args.epochs)

{'batch_size': 32, 'epochs': 64}
32
64