A “frozen” dictionary for Python
1–10 of 172 posts
Re: A “frozen” dictionary for Python
#2Next step: Auto-inferring the correct (most narrow) TypedDict type from a frozendict. (Think `const foo = { … } as const` in TypeScript.) I miss this TS feature in Python on the daily.
Re: A “frozen” dictionary for Python
#3Shoutout to pyrsistent, a personal favorite library for frozen/immutable/hashable data structures whenever I need to use lists, sets, or dicts as dict keys, or make sets of such items: https://github.com/tobgu/pyrsistent
Re: A “frozen” dictionary for Python
#4Next step: Auto-inferring the correct (most narrow) TypedDict type from a frozendict. (Think `const foo = { … } as const` in TypeScript.) I miss this TS feature in Python on the daily.
Can you give a Python example of a use case for this?
Re: A “frozen” dictionary for Python
#5Next step: Auto-inferring the correct (most narrow) TypedDict type from a frozendict. (Think `const foo = { … } as const` in TypeScript.) I miss this TS feature in Python on the daily.
I also SUPER LOVE this feature. Especially when you make a type union of the keys for easier indexing.
Re: A “frozen” dictionary for Python
#6A frozen dictionary would be very welcome. You can already do something similar using MappingProxyType [0]
from types import MappingProxyType
d = {}
d["a"] = 1
d["b"] = 2
print(d)
frozen = MappingProxyType(d)
print(frozen["a"])
# Error:
frozen["b"] = "new"
Re: A “frozen” dictionary for Python
#7If this gets wide enough use, they could add an optimization for code like this:
n = 1000
a = {}
for i in range(n):
a[i] = str(i)
a = frozendict(a) # O(n) operation can be turned to O(1)
Re: A “frozen” dictionary for Python
#8Great! Now make `set` have a stable order and we're done here.
Re: A “frozen” dictionary for Python
#9Next step: Auto-inferring the correct (most narrow) TypedDict type from a frozendict. (Think `const foo = { … } as const` in TypeScript.) I miss this TS feature in Python on the daily.
Curious what this means for typescript as well; honestly I've only reached for as const rarely.
Re: A “frozen” dictionary for Python
#10Next step: Auto-inferring the correct (most narrow) TypedDict type from a frozendict. (Think `const foo = { … } as const` in TypeScript.) I miss this TS feature in Python on the daily.
What would that do exactly? Auto-generate a TypedDict class?
Bringing up TypedDict is sort of interesting, because it seems like a frozen dictionary could have been implemented by PEP 705, if typing.ReadOnly was enforced at runtime, and not just a hint to a static type checker.