63 lines
2.4 KiB
Markdown
63 lines
2.4 KiB
Markdown
# Iterable interface
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Iterable is a class that provides function that creates _the iterator_:
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class Iterable {
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abstract fun iterator()
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}
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Note that each call of `iterator()` must provide an independent iterator.
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Iterator itself is a simple interface that should provide only to method:
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class Iterator {
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abstract fun hasNext(): Bool
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fun next(): Obj
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}
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Just remember at this stage typed declarations are not yet supported.
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Having `Iterable` in base classes allows to use it in for loop. Also, each `Iterable` has some utility functions available:
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## Instance methods
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| fun/method | description |
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|-----------------|---------------------------------------------------------------------------------|
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| toList() | create a list from iterable |
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| toSet() | create a set from iterable |
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| contains(i) | check that iterable contains `i` |
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| `i in iterator` | same as `contains(i)` |
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| isEmpty() | check iterable is empty |
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| forEach(f) | call f for each element |
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| toMap() | create a map from list of key-value pairs (arrays of 2 items or like) |
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| map(f) | create a list of values returned by `f` called for each element of the iterable |
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| indexOf(i) | return index if the first encounter of i or a negative value if not found |
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| associateBy(kf) | create a map where keys are returned by kf that will be called for each element |
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fun Iterable.toList(): List
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fun Iterable.toSet(): Set
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fun Iterable.indexOf(element): Int
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fun Iterable.contains(element): Bool
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fun Iterable.isEmpty(element): Bool
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fun Iterable.forEach(block: (Any?)->Void ): Void
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fun Iterable.map(block: (Any?)->Void ): List
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fun Iterable.associateBy( keyMaker: (Any?)->Any): Map
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## Abstract methods
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fun iterator(): Iterator
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Creates a list by iterating to the end. So, the Iterator should be finite to be used with it.
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## Included in interfaces:
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- [Collection], Array, [List]
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## Implemented in classes:
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- [List], [Range]
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[List]: List.md
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[Range]: Range.md |