Svector (pronounced Swag-tor) provides extension methods to pyrsistent data structures.
Easily chain your methods confidently with tons of additional methods. Leverage
the latest mypy features to spot errors during coding.

Build Status

pip install svector

Immutable list replacement for python. With postfix methods for easy functional programming.

Quick Start

With mypy installed, easily spot errors when you call the wrong methods on your sequence.

from svector import Svector

many_strings = Svector.of(["Lucy, Damion, Jon"])  # Svector[str]
many_strings.sum()  # Mypy errors with 'Invalid self argument'. You can't sum a sequence of strings!

many_nums = Svector.of([1, 1.2])
assert many_nums.sum() == 2.2  # ok!

class CannotSortMe:
    def __init__(self, value: int):
        self.value: int = value

stuff = Svector.of([CannotSortMe(value=1), CannotSortMe(value=1)])
stuff.sort_by(lambda x: x)  # Mypy errors with 'Cannot be "CannotSortMe"'. You can't sort by the class itself
stuff.sort_by(lambda x: x.value)  # ok! You can sort by the value

Svector.of([{"i am a dict": "value"}]).distinct_by(
    lambda x: x
)  # Mypy errors with 'Cannot be Dict[str, str]. You can't hash a dict itself

Svector provides methods that you can chain easily for easier data processing.

from svector import Svector

Svector.of([-1, 0, 1]).map(
    lambda x: x if x >= 0 else None).flatten_option()  # Mypy infers Svector[int] correctly

result = (
    Svector.of(i for i in range(5000))
    .map(lambda x: (x % 3, x))
    .filter(lambda x: x[0] == 0)
    .for_each_enumerate(lambda idx, element: print(f"{idx}: {element}"))


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