Question

What’s the most succinct way of saying, in Python, “Give me dict['foo'] if it exists, and if not, give me this other value bar“? If I were using an object rather than a dictionary, I’d use getattr:

getattr(obj, 'foo', bar)

but this raises a key error if I try using a dictionary instead (a distinction I find unfortunate coming from JavaScript/CoffeeScript). Likewise, in JavaScript/CoffeeScript I’d just write

dict['foo'] || bar

but, again, this yields a KeyError. What to do? Something succinct, please!

Answer 1

dict.get(key, default) returns dict[key] if key in dict, else returns default.

Note that the default for default is None so if you say dict.get(key) and key is not in dict then this will just return None rather than raising a KeyError as happens when you use the [] key access notation.