fast-digits: Integer-to-digits conversion.
Convert an integer to digits and back. This library is both asymptotically (O(n^1.4) vs. O(n^2)) and practically (2x-40x for typical inputs) faster than Data.Digits.
[Skip to Readme]
library fast-digits
library fast-digits:fast-digits-internal
Downloads
- fast-digits-0.3.2.0.tar.gz [browse] (Cabal source package)
- Package description (revised from the package)
Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.
Maintainer's Corner
For package maintainers and hackage trustees
Candidates
- No Candidates
| Versions [RSS] | 0.1.0.0, 0.2.0.0, 0.2.1.0, 0.3.0.0, 0.3.1.0, 0.3.2.0 |
|---|---|
| Change log | changelog.md |
| Dependencies | base (>=4.15 && <5), fast-digits, ghc-bignum (<1.4) [details] |
| Tested with | ghc ==9.0.2, ghc ==9.2.8, ghc ==9.4.8, ghc ==9.6.7, ghc ==9.8.4, ghc ==9.10.2, ghc ==9.12.2 |
| License | GPL-3.0-only |
| Author | Andrew Lelechenko |
| Maintainer | andrew.lelechenko@gmail.com |
| Revised | Revision 1 made by Bodigrim at 2025-07-15T21:52:11Z |
| Category | Data |
| Home page | https://github.com/Bodigrim/fast-digits |
| Source repo | head: git clone https://github.com/Bodigrim/fast-digits |
| Uploaded | by Bodigrim at 2023-07-29T20:06:59Z |
| Distributions | LTSHaskell:0.3.2.0, NixOS:0.3.2.0, Stackage:0.3.2.0 |
| Reverse Dependencies | 2 direct, 0 indirect [details] |
| Downloads | 3641 total (12 in the last 30 days) |
| Rating | (no votes yet) [estimated by Bayesian average] |
| Your Rating | |
| Status | Docs available [build log] Last success reported on 2023-07-29 [all 1 reports] |
Readme for fast-digits-0.3.2.0
[back to package description]fast-digits 
The fastest Haskell library to split integers into digits. It is both asymptotically (O(n1.4) vs. O(n2)) and practically (2x-40x for typical inputs) faster than Data.Digits.
Here are benchmarks for GHC 8.10:
> cabal bench -w ghc-8.10.4
All
short
2
FastDigits: OK (3.11s)
12.3 ms ± 701 μs
Data.Digits: OK (1.41s)
22.2 ms ± 1.8 ms, 1.81x
10
FastDigits: OK (2.11s)
4.16 ms ± 369 μs
Data.Digits: OK (3.74s)
7.40 ms ± 235 μs, 1.78x
100000
FastDigits: OK (4.89s)
1.20 ms ± 69 μs
Data.Digits: OK (3.96s)
1.95 ms ± 78 μs, 1.63x
1000000000
FastDigits: OK (4.02s)
985 μs ± 62 μs
Data.Digits: OK (3.15s)
1.54 ms ± 70 μs, 1.56x
medium
2
FastDigits: OK (3.02s)
1.49 ms ± 66 μs
Data.Digits: OK (1.42s)
5.62 ms ± 542 μs, 3.77x
10
FastDigits: OK (2.35s)
571 μs ± 42 μs
Data.Digits: OK (1.77s)
1.76 ms ± 152 μs, 3.07x
100000
FastDigits: OK (3.87s)
238 μs ± 19 μs
Data.Digits: OK (3.44s)
419 μs ± 23 μs, 1.76x
1000000000
FastDigits: OK (3.05s)
186 μs ± 13 μs
Data.Digits: OK (4.42s)
268 μs ± 11 μs, 1.44x
long
2
FastDigits: OK (3.75s)
3.60 ms ± 215 μs
Data.Digits: OK (1.89s)
125 ms ± 9.6 ms, 34.88x
10
FastDigits: OK (2.30s)
2.24 ms ± 125 μs
Data.Digits: OK (2.47s)
39.0 ms ± 2.0 ms, 17.40x
100000
FastDigits: OK (1.93s)
1.88 ms ± 139 μs
Data.Digits: OK (4.52s)
8.82 ms ± 533 μs, 4.70x
1000000000
FastDigits: OK (1.77s)
1.71 ms ± 149 μs
Data.Digits: OK (1.35s)
5.30 ms ± 482 μs, 3.10x