A get() like method for checking for Python attributes
Question:
If I had a dictionary dict and I wanted to check for dict['key'] I could either do so in a try block (bleh!) or use the get() method, with False as a default value.
I’d like to do the same thing for object.attribute. That is, I already have object to return False if it hasn’t been set, but then that gives me errors like
AttributeError: ‘bool’ object has no attribute ‘attribute’
Answers:
Do you mean hasattr() perhaps?
hasattr(object, "attribute name") #Returns True or False
Python.org doc – Built in functions – hasattr()
You can also do this, which is a bit more cluttered and doesn’t work for methods.
"attribute" in obj.__dict__
For checking if a key is in a dictionary you can use in: 'key' in dictionary.
For checking for attributes in object use the hasattr() function: hasattr(obj, 'attribute')
A more direct analogue to dict.get(key, default) than hasattr is getattr.
val = getattr(obj, 'attr_to_check', default_value)
(Where default_value is optional, raising an exception on no attribute if not found.)
For your example, you would pass False.
If I had a dictionary dict and I wanted to check for dict['key'] I could either do so in a try block (bleh!) or use the get() method, with False as a default value.
I’d like to do the same thing for object.attribute. That is, I already have object to return False if it hasn’t been set, but then that gives me errors like
AttributeError: ‘bool’ object has no attribute ‘attribute’
Do you mean hasattr() perhaps?
hasattr(object, "attribute name") #Returns True or False
Python.org doc – Built in functions – hasattr()
You can also do this, which is a bit more cluttered and doesn’t work for methods.
"attribute" in obj.__dict__
For checking if a key is in a dictionary you can use in: 'key' in dictionary.
For checking for attributes in object use the hasattr() function: hasattr(obj, 'attribute')
A more direct analogue to dict.get(key, default) than hasattr is getattr.
val = getattr(obj, 'attr_to_check', default_value)
(Where default_value is optional, raising an exception on no attribute if not found.)
For your example, you would pass False.