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Uncomment binarySearchBy overload taking a Comparator #5137

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03a795d
Uncomment `binarySearchBy` overload taking a `Comparator`
YoshiRulz May 25, 2023
e4fcd41
Remove not applicable line from `binarySearch` docs re: null
YoshiRulz May 25, 2023
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22 changes: 17 additions & 5 deletions libraries/stdlib/src/kotlin/collections/Collections.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -350,8 +350,6 @@ public fun <T : Comparable<T>> List<T?>.binarySearch(element: T?, fromIndex: Int
*
* If the list contains multiple elements equal to the specified [element], there is no guarantee which one will be found.
*
* `null` value is considered to be less than any non-null value.
*
* @return the index of the element, if it is contained in the list within the specified range;
* otherwise, the inverted insertion point `(-insertion point - 1)`.
* The insertion point is defined as the index at which the element should be inserted,
Expand Down Expand Up @@ -403,9 +401,23 @@ public inline fun <T, K : Comparable<K>> List<T>.binarySearchBy(
): Int =
binarySearch(fromIndex, toIndex) { compareValues(selector(it), key) }

// do not introduce this overload --- too rare
//public fun <T, K> List<T>.binarySearchBy(key: K, comparator: Comparator<K>, fromIndex: Int = 0, toIndex: Int = size(), selector: (T) -> K): Int =
// binarySearch(fromIndex, toIndex) { comparator.compare(selector(it), key) }
/**
* Searches this list or its range for an element having the key returned by the specified [selector] function
* equal to the provided [key] value using the binary search algorithm.
* The list is expected to be sorted into ascending order according to the ordering of keys of its elements as given by the specified [comparator].
* otherwise the result is undefined.
*
* If the list contains multiple elements with the specified [key], there is no guarantee which one will be found.
*
* @return the index of the element with the specified [key], if it is contained in the list within the specified range;
* otherwise, the inverted insertion point `(-insertion point - 1)`.
* The insertion point is defined as the index at which the element should be inserted,
* so that the list (or the specified subrange of list) still remains sorted.
* @sample samples.collections.Collections.Lists.binarySearchByKey
* @sample samples.collections.Collections.Lists.binarySearchWithComparator
*/
public fun <T, K> List<T>.binarySearchBy(key: K, comparator: Comparator<K>, fromIndex: Int = 0, toIndex: Int = size, selector: (T) -> K): Int =
binarySearch(fromIndex, toIndex) { comparator.compare(selector(it), key) }


/**
Expand Down