- Notifications
You must be signed in to change notification settings - Fork1
a proposal to add a method to iterators for producing an iterator of its subsequences
tc39/proposal-iterator-chunking
Folders and files
| Name | Name | Last commit message | Last commit date | |
|---|---|---|---|---|
Repository files navigation
A TC39 proposal to consume an iterator as either overlapping or non-overlapping subsequences of configurable size.
Stage: 2.7
Specification:https://tc39.es/proposal-iterator-chunking/
It can be useful to consume a stream by more than one value at a time. For example, certain algorithms require looking at adjacent elements.
This is commonly solved for non-overlapping subsequences with a "chunking" method that works like the following:
constdigits=()=>[0,1,2,3,4,5,6,7,8,9].values();letchunksOf2=Array.from(digits().chunks(2));// [ [0, 1], [2, 3], [4, 5], [6, 7], [8, 9] ]letchunksOf3=Array.from(digits().chunks(3));// [ [0, 1, 2], [3, 4, 5], [6, 7, 8], [9] ]letchunksOf4=Array.from(digits().chunks(4));// [ [0, 1, 2, 3], [4, 5, 6, 7], [8, 9] ]
- pagination
- columnar/grid layouts, such as calendars
- batch/stream processing
- matrix operations
- formatting/encoding
- bucketing (using a computed chunk size, for iterators of known size)
When overlapping sequences are needed, this is commonly called a "sliding window".
letwindowsOf2=Array.from(digits().windows(2));// [ [0, 1], [1, 2], [2, 3], [3, 4], [4, 5], [5, 6], [6, 7], [7, 8], [8, 9] ]letwindowsOf3=Array.from(digits().windows(3));// [ [0, 1, 2], [1, 2, 3], [2, 3, 4], [3, 4, 5], [4, 5, 6], [5, 6, 7], [6, 7, 8], [7, 8, 9] ]letwindowsOf4=Array.from(digits().windows(4));// [ [0, 1, 2, 3], [1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6], [4, 5, 6, 7], [5, 6, 7, 8], [6, 7, 8, 9] ]
- running/continuous computations, such as averages
- context-sensitive algorithms, such as pairwise comparisons
- carousels and their analogues (when applied to an infinite cycle)
| language | library | chunks | windows | chunks of 0? | truncates windows? |
|---|---|---|---|---|---|
| C++ | std::ranges::views | chunk | slide | undefined behavior | no |
| Clojure | core | partition | partition | infinite empty lists | when insufficient padding; terminates after 1 |
| Elm | List.Extra | groupsOf | groupsOfWithStep | empty list | no |
| Haskell | split | chunksOf | divvy | infinite empty lists | yes |
| Java | Stream | Gatherers.windowFixed | Gatherers.windowSliding | throws | no, step not configurable |
| Kotlin | Iterable | chunked | windowed | throws | configurable via parameter |
| .NET | System.Linq | Enumerable.Chunk | -- | throws | N/A |
| PHP | array | array_chunk | -- | throws | N/A |
| Python | itertools (3.12) | batched | -- | ?? | N/A |
| Python | more-itertools | grouper | windowed | empty iterator | no, mandatory fill value |
| Ruby | Enumerable | each_slice | each_cons | throws | no, step not configurable |
| Rust | Iterator | array_chunks | map_windows | panics | no, step not configurable |
| Rust | slice | chunks | windows | panics | no, step not configurable |
| Scala | Seq | grouped | sliding | throws | yes |
| Swift | Sequence | -- | -- | N/A | N/A |
| library | chunks | windows | chunks of 0? | truncates windows? |
|---|---|---|---|---|
chunk | chunk | -- | coerces 0 to false 😞 | N/A |
extra-iterable | chunk | chunk | infinite empty arrays | yes |
iter-ops | page | -- | throws | N/A |
iter-tools | batch | window,windowAhead,windowBehind | throws | optionally |
iterablefu | chunk | -- | collects everything into a single array | N/A |
itertools-ts | chunkwise | chunkwiseOverlap | throws | yes |
| Lodash / Underscore | chunk | -- | infinite empty arrays | N/A |
| Ramda | splitEvery | aperture | infinite empty arrays | no |
| sequency | chunk | -- | throws | N/A |
| wu | chunk | -- | collects everything into a single array | N/A |
About
a proposal to add a method to iterators for producing an iterator of its subsequences
Resources
Code of conduct
Contributing
Security policy
Uh oh!
There was an error while loading.Please reload this page.
Stars
Watchers
Forks
Uh oh!
There was an error while loading.Please reload this page.
Contributors2
Uh oh!
There was an error while loading.Please reload this page.