Python dictionary - binary search for a key?

Question

I want to write a container class that acts like a dictionary (actually derives from a dict), The keys for this structure will be dates.

When a key (i.e. date) is used t

Answer 1

The sortedcontainers module provides a SortedDict type that maintains the keys in sorted order and supports bisecting on those keys. The module is pure-Python and fast-as-C implementations with 100% test coverage and hours of stress.

For example:

from sortedcontainers import SortedDict

sd = SortedDict((date, value) for date, value in data)

# Bisect for the index of the desired key.
index = sd.bisect('2001/01/05')

# Lookup the real key at that index.
key = sd.iloc[index]

# Retrieve the value associated with that key.
value = sd[key]

Because SortedDict supports fast indexing, it's easy to look ahead or behind your key as well. SortedDict is also a MutableMapping so it should work nicely in your type system.