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https://issues.apache.org/jira/browse/GROOVY-11596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Paul King updated GROOVY-11596:
-------------------------------
Description:
This issue is to provide a few more iterator variants in the DGM methods. Some
of these methods already exist but have an eager implementation. Others are
inspired from [groovy-stream|https://timyates.github.io/groovy-stream/].
Instead of being executing in multiple seconds, as is, the following code
executes in a few 10s of ms with the iterator line uncommented, and creates
much fewer intermediate collections.
{code:groovy}
assert (1..10000)
// .iterator()
.repeat(10000)
.take(20000000)
.takeWhile{ true }
.drop(5)
.toUnique()
.collate(2)
.flatten{ it * 2 }
.dropRight(1)
.dropWhile{ it < 15 }
.withIndex()
.init()
.take(5)
.injectAll([0, 0]){ a, b -> [a.first() + b.first(), a.last() + b.last()] }
.collect()
.toString() == '[[16, 0], [34, 1], [54, 3], [76, 6], [100, 10]]'
{code}
In the above example, the existing methods on iterators are: drop, init, take,
takeWhile, withIndex, dropRight, toUnique
Existing methods on iterables only: collate, flatten
Existing eager iterator methods: injectAll
New methods: repeat (this is an alias for multiple when giving a count but
matches groovy-stream and makes more sense when using the infinite count)
was:
This issue is to provide a few more iterator variants in the DGM methods. Some
of these methods already exist but have an eager implementation. Others are
inspired from [groovy-stream|https://timyates.github.io/groovy-stream/].
Instead of being executing in multiple seconds, as is, the following code
executes in a few 10s of ms with the iterator line uncommented, and creates
much fewer intermediate collections.
{code:groovy}
assert (1..10000)
// .iterator()
.repeat(10000)
.take(20000000)
.takeWhile{ true }
.drop(5)
.collate(2)
.flatten{ it * 2 }
.dropRight(1)
.dropWhile{ it < 15 }
.withIndex()
.init()
.take(5)
.injectAll([0, 0]){ a, b -> [a.first() + b.first(), a.last() + b.last()] }
.collect()
.toString() == '[[16, 0], [34, 1], [54, 3], [76, 6], [100, 10]]'
{code}
> Additional DGM lazy iterator methods
> ------------------------------------
>
> Key: GROOVY-11596
> URL: https://issues.apache.org/jira/browse/GROOVY-11596
> Project: Groovy
> Issue Type: Improvement
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
> This issue is to provide a few more iterator variants in the DGM methods.
> Some of these methods already exist but have an eager implementation. Others
> are inspired from [groovy-stream|https://timyates.github.io/groovy-stream/].
> Instead of being executing in multiple seconds, as is, the following code
> executes in a few 10s of ms with the iterator line uncommented, and creates
> much fewer intermediate collections.
> {code:groovy}
> assert (1..10000)
> // .iterator()
> .repeat(10000)
> .take(20000000)
> .takeWhile{ true }
> .drop(5)
> .toUnique()
> .collate(2)
> .flatten{ it * 2 }
> .dropRight(1)
> .dropWhile{ it < 15 }
> .withIndex()
> .init()
> .take(5)
> .injectAll([0, 0]){ a, b -> [a.first() + b.first(), a.last() + b.last()] }
> .collect()
> .toString() == '[[16, 0], [34, 1], [54, 3], [76, 6], [100, 10]]'
> {code}
> In the above example, the existing methods on iterators are: drop, init,
> take, takeWhile, withIndex, dropRight, toUnique
> Existing methods on iterables only: collate, flatten
> Existing eager iterator methods: injectAll
> New methods: repeat (this is an alias for multiple when giving a count but
> matches groovy-stream and makes more sense when using the infinite count)
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