关于hasattr()、getattr()、setattr()函数的使用
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当我们定义一个类及其相关对象时
- hasattr()
- getattr()
- setattr()
为了举例说明，先定义一个类
class DP(object):
"""process data"""
def __init__(self,root=None,file_name=None,is_load=True):
self._root=root
self._file_name=file_name
self._is_load=is_load
self._data=None1.hasattr()：判断对象是否具有给定名字的属性
源码：
def hasattr(*args, **kwargs): # real signature unknown
"""
Return whether the object has an attribute with the given name.
This is done by calling getattr(obj, name) and catching AttributeError.
"""
pass举例说明：
dp=DP()
if hasattr(dp,'_root'):
print(True)
else:
print(False)结果是：True
2.getattr():获取对象的某属性的值
源码：
def getattr(object, name, default=None): # known special case of getattr
"""
getattr(object, name[, default]) -> value
Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.
When a default argument is given, it is returned when the attribute doesn't
exist; without it, an exception is raised in that case.
"""
pass举例说明：
当我们选择默认值时：
dp=DP()
print(getattr(dp,'_root'))
结果是:None
当我们定义对象时，设置属性值：
dp=DP(root='PATH')
print(getattr(dp,'_root'))
结果是：PATH当对象缺乏预先定义的属性名时
源码：
def setattr(x, y, v): # real signature unknown; restored from __doc__
"""
Sets the named attribute on the given object to the specified value.
setattr(x, 'y', v) is equivalent to ``x.y = v''
"""
pass举例说明：
dp=DP()
#判断是否有某个属性，如果没有，则为对象设置相应的属性
if hasattr(dp,'_dir'):
print(True)
else:
setattr(dp,'_dir','random_value')全部评论 (0)
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