This is a drop in replacement for the built-in mutable python list
But with more post-fixed methods for chaining in a typesafe manner!!
Leverage the latest pyright features to spot errors during coding.
All these methods return a new list. They do not mutate the original list.
Not able to convince your colleagues to use immutable functional data structures? I understand.
This library lets you still have the benefits of typesafe chaining methods while letting your colleagues have their mutable lists!
pip install slist
Easily spot errors when you call the wrong methods on your sequence with mypy.
from slist import Slist
many_strings = Slist(["Lucy, Damion, Jon"]) # Slist[str]
many_strings.sum() # Mypy errors with 'Invalid self argument'. You can't sum a sequence of strings!
many_nums = Slist([1, 1.2])
assert many_nums.sum() == 2.2 # ok!
class CannotSortMe:
def __init__(self, value: int):
self.value: int = value
stuff = Slist([CannotSortMe(value=1), CannotSortMe(value=1)])
stuff.sort_by(lambda x: x) # Mypy errors with 'Cannot be "CannotSortMe"'. There isn't a way to sort by the class itself
stuff.sort_by(lambda x: x.value) # ok! You can sort by the value
Slist([{"i am a dict": "value"}]).distinct_by(
lambda x: x
) # Mypy errors with 'Cannot be Dict[str, str]. You can't hash a dict itselfSlist provides methods to easily flatten and infer the types of your data.
from slist import Slist, List
from typing import Optional
test_optional: Slist[Optional[int]] = Slist([-1, 0, 1]).map(
lambda x: x if x >= 0 else None
)
# Mypy infers slist[int] correctly
test_flattened: Slist[int] = test_optional.flatten_option()
test_nested: Slist[List[str]] = Slist([["bob"], ["dylan", "chan"]])
# Mypy infers slist[str] correctly
test_flattened_str: Slist[str] = test_nested.flatten_list()There are plenty more methods to explore!
from slist import Slist
result = (
Slist([1, 2, 3])
.repeat_until_size_or_raise(20)
.grouped(2)
.map(lambda inner_list: inner_list[0] + inner_list[1] if inner_list.length == 2 else inner_list[0])
.flatten_option()
.distinct_by(lambda x: x)
.map(str)
.reversed()
.mk_string(sep=",")
)
assert result == "5,4,3"
