Python getattr method
getattr() function is used to return an object property value.
gatattr() function returns the value of the named attribute of the object. name must be a string. If the string is the name of one of the objects variables, the result is the value of that variable.
getattr(x, 'name') is equivalent to
x.name. If the named variable does not exist, defaultis returned if provided, otherwise AttributeError is raised.
The advantage is that when writing a project, the input received is a string, and the getattr function makes it easy to use the methods and properties of the class from the user's perspective.
There are also methods with attr such as hasattr, setattr, etc
Related course: Complete Python Programming Course & Exercises
getattr(object, name[, default])
- object -- object.
- name -- string, object property.
- default -- the default return value, if not provided, will trigger AttributeError in the absence of a corresponding attribute.
- Returns the object property value.
First, let's look at getattr, as the name suggests, to get the property. It should all be
getattr(object, "attribution",None), in general we use
getattr(object,name) It is similar to getting the value of object.attribution.
Usage of getattr.
>>> class test: ... cal=1 ... >>> getattr(test, "cal") 1 >>> test.cal 1 >>>
The following example shows how getattr is used.
>>> class A: ... b = 3 ... c = 4 ... >>> >>> # directly on class >>> getattr(A,'b') 3 >>> # create object >>> obj = A() >>> getattr(obj,'b') 3 >>> getattr(obj,'c') 4 >>>
>>> class A(object): ... bar = 1 ... >>> a = A() >>> getattr(a, 'bar') # Get property bar value 1 >>> getattr(a, 'bar2') # attribute bar2 does not exist, trigger exception Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'A' object has no attribute 'bar2' >>> getattr(a, 'bar2', 3) # property bar2 does not exist, but default value 3 is set