Python getattr equivalent for dictionaries?

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 a

Answer 1

Also take a look at collections module's defaultdict class. It's a dict for which you can specify what it must return when the key is not found. With it you can do things like:

class MyDefaultObj:
    def __init__(self):
        self.a = 1

from collections import defaultdict
d = defaultdict(MyDefaultObj)
i = d['NonExistentKey']
type(i)

which allows you to use the familiar d[i] convention.

However, as mikej said, .get() also works, but here is the form closer to your JavaScript example:

d = {}
i = d.get('NonExistentKey') or MyDefaultObj()
# the reason this is slightly better than d.get('NonExistent', MyDefaultObj())
# is that instantiation of default value happens only when 'NonExistent' does not exist.
# With d.get('NonExistent', MyDefaultObj()) you spin up a default every time you .get()
type(i)