This release is a pre-release and may not be stable for production use.
Lazy, immutable, infinite numeric sequences for Python.
countably lets you describe sequences declaratively, the way you’d write them on paper, and evaluate them on demand:
from countably import count, constant
triangular = count() * (count() + 1) // 2 # 0, 1, 3, 6, 10, ...
powers_of_two = 2 ** count() # 1, 2, 4, 8, 16, ...
every_third = count()[2::3] # 2, 5, 8, 11, ...The primitives are just constant and count. Arithmetic, comparisons, slicing, and element-wise maximum / minimum build everything else. Plain numbers are coerced automatically, so 3 + 5 * count() is equivalent to constant(3) + constant(5) * count().
Highlights
Lazy – elements are computed only on access, with a per-instance 100-item LRU cache for random access. Iteration walks the inputs directly, bypassing the cache.
Immutable – every operation produces a new sequence; nothing is mutated.
Iterable, not iterator – iter(seq) starts fresh every time.
Slices are lazy too – seq[2::3] stays infinite, seq[2:10] is finite with a real len(). Arithmetic between sequences uses the shorter length.
Round / floor / ceil / trunc are supported through the standard Python protocols (math.floor(seq), round(seq)).
Comparisons (<, <=, >, >=) return sequences of booleans, which are numbers in the same world.
See doc/quick-start.rst for usage including a Fibonacci one-liner.
Install
pip install countably1 maintainer
Release files for countably 2026.5.16.79282rc1
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| countably-2026.5.16.79282rc1.tar.gz | 11.1 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| countably-2026.5.16.79282rc1-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 23.1 kB
Release files / countably-2026.5.16.79282rc1.tar.gz
| Download URL | countably-2026.5.16.79282rc1.tar.gz |
|---|---|
| Size | 11.1 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
191d344dd2273da833e4a57114a3ef6483271b121386d05fe075dd01809f374b
|
|
BLAKE2b-256 checksum How to use checksums |
376127cbdbf8a07722b6a13102bba1e6cba498a3ed16bf76d48346c2b5e752e6
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.13
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on May 16, 2026.
Transparency logRelease files / countably-2026.5.16.79282rc1-py3-none-any.whl
| Download URL | countably-2026.5.16.79282rc1-py3-none-any.whl |
|---|---|
| Size | 12.0 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
bf174292f830fba25b980c3688440b7ce1f103ae974e393d0e850b6600bb2610
|
|
BLAKE2b-256 checksum How to use checksums |
d1c12d7a45d0a57e18d2554f3dc20f8fe1e4ca99057200c8e2ee3b52f0e78e48
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/6.1.0 CPython/3.13.13
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on May 16, 2026.
Transparency log
