CODEWITHSUNDEEP
pythonattributes
JJ.
JJ.

Reputation: 5084

A get() like method for checking for Python attributes

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'

Upvotes: 97

Views: 51301

Answers (3)

Zoomulator
Zoomulator

Reputation: 21200

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__

Upvotes: 21

Brian
Brian

Reputation: 119231

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.

Upvotes: 152

unbeknown
unbeknown

Reputation:

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')

Upvotes: 7

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