Python 如何检查一个变量是否存在

我们使用下面的代码来检查一个变量是否存在于Python中。

例子

x =10
class foo:
g = 'rt'
def bar(self):
m=6
print (locals())
if 'm' in locals():
print ('m is local variable')
else:
print ('m is not a local variable')
f = foo()
f.bar()
print (globals())
if hasattr(f, 'g'):
print ('g is an attribute')
else:
print ("g is not an attribute")
if 'x' in globals():
print ('x is a global variable')

输出

我们得到以下输出

{'self': <__main__.foo instance at 0x0000000002E24EC8>, 'm': 6}
m is local variable
{'f': <__main__.foo instance at 0x0000000002E24EC8>, '__builtins__': <module '__builtin__' (built-in)>, '__file__': 'C:/Users/TutorialsPoint1/~.py', '__package__': None, 'x': 10, '__name__': '__main__', 'foo': <class __main__.foo at 0x0000000002D29828>, '__doc__': None}
g is an attribute
x is a global variable
Process finished with exit code 0