//
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// ArrayExtensions.swift
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// SwifterSwift
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//
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// Created by Omar Albeik on 8/5/16.
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// Copyright © 2016 SwifterSwift
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//
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// MARK: - Methods
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public extension Array {
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/// SwifterSwift: Insert an element at the beginning of array.
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///
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/// [2, 3, 4, 5].prepend(1) -> [1, 2, 3, 4, 5]
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/// ["e", "l", "l", "o"].prepend("h") -> ["h", "e", "l", "l", "o"]
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///
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/// - Parameter newElement: element to insert.
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mutating func prepend(_ newElement: Element) {
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insert(newElement, at: 0)
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}
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/// SwifterSwift: Safely swap values at given index positions.
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///
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/// [1, 2, 3, 4, 5].safeSwap(from: 3, to: 0) -> [4, 2, 3, 1, 5]
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/// ["h", "e", "l", "l", "o"].safeSwap(from: 1, to: 0) -> ["e", "h", "l", "l", "o"]
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///
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/// - Parameters:
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/// - index: index of first element.
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/// - otherIndex: index of other element.
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mutating func safeSwap(from index: Index, to otherIndex: Index) {
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guard index != otherIndex else { return }
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guard startIndex..<endIndex ~= index else { return }
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guard startIndex..<endIndex ~= otherIndex else { return }
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swapAt(index, otherIndex)
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}
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/// SwifterSwift: Sort an array like another array based on a key path. If the other array doesn't contain a certain value, it will be sorted last.
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///
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/// [MyStruct(x: 3), MyStruct(x: 1), MyStruct(x: 2)].sorted(like: [1, 2, 3], keyPath: \.x)
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/// -> [MyStruct(x: 1), MyStruct(x: 2), MyStruct(x: 3)]
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///
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/// - Parameters:
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/// - otherArray: array containing elements in the desired order.
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/// - keyPath: keyPath indiciating the property that the array should be sorted by
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/// - Returns: sorted array.
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func sorted<T: Hashable>(like otherArray: [T], keyPath: KeyPath<Element, T>) -> [Element] {
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let dict = otherArray.enumerated().reduce(into: [:]) { $0[$1.element] = $1.offset }
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return sorted {
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guard let thisIndex = dict[$0[keyPath: keyPath]] else { return false }
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guard let otherIndex = dict[$1[keyPath: keyPath]] else { return true }
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return thisIndex < otherIndex
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}
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}
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}
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// MARK: - Methods (Equatable)
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public extension Array where Element: Equatable {
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/// SwifterSwift: Remove all instances of an item from array.
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///
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/// [1, 2, 2, 3, 4, 5].removeAll(2) -> [1, 3, 4, 5]
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/// ["h", "e", "l", "l", "o"].removeAll("l") -> ["h", "e", "o"]
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///
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/// - Parameter item: item to remove.
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/// - Returns: self after removing all instances of item.
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@discardableResult
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mutating func removeAll(_ item: Element) -> [Element] {
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removeAll(where: { $0 == item })
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return self
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}
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/// SwifterSwift: Remove all instances contained in items parameter from array.
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///
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/// [1, 2, 2, 3, 4, 5].removeAll([2,5]) -> [1, 3, 4]
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/// ["h", "e", "l", "l", "o"].removeAll(["l", "h"]) -> ["e", "o"]
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///
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/// - Parameter items: items to remove.
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/// - Returns: self after removing all instances of all items in given array.
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@discardableResult
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mutating func removeAll(_ items: [Element]) -> [Element] {
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guard !items.isEmpty else { return self }
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removeAll(where: { items.contains($0) })
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return self
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}
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/// SwifterSwift: Remove all duplicate elements from Array.
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///
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/// [1, 2, 2, 3, 4, 5].removeDuplicates() -> [1, 2, 3, 4, 5]
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/// ["h", "e", "l", "l", "o"]. removeDuplicates() -> ["h", "e", "l", "o"]
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///
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/// - Returns: Return array with all duplicate elements removed.
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@discardableResult
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mutating func removeDuplicates() -> [Element] {
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// Thanks to https://github.com/sairamkotha for improving the method
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self = reduce(into: [Element]()) {
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if !$0.contains($1) {
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$0.append($1)
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}
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}
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return self
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}
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/// SwifterSwift: Return array with all duplicate elements removed.
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///
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/// [1, 1, 2, 2, 3, 3, 3, 4, 5].withoutDuplicates() -> [1, 2, 3, 4, 5])
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/// ["h", "e", "l", "l", "o"].withoutDuplicates() -> ["h", "e", "l", "o"])
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///
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/// - Returns: an array of unique elements.
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///
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func withoutDuplicates() -> [Element] {
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// Thanks to https://github.com/sairamkotha for improving the method
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return reduce(into: [Element]()) {
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if !$0.contains($1) {
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$0.append($1)
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}
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}
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}
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/// SwifterSwift: Returns an array with all duplicate elements removed using KeyPath to compare.
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///
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/// - Parameter path: Key path to compare, the value must be Equatable.
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/// - Returns: an array of unique elements.
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func withoutDuplicates<E: Equatable>(keyPath path: KeyPath<Element, E>) -> [Element] {
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return reduce(into: [Element]()) { (result, element) in
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if !result.contains(where: { $0[keyPath: path] == element[keyPath: path] }) {
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result.append(element)
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}
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}
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}
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/// SwifterSwift: Returns an array with all duplicate elements removed using KeyPath to compare.
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///
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/// - Parameter path: Key path to compare, the value must be Hashable.
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/// - Returns: an array of unique elements.
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func withoutDuplicates<E: Hashable>(keyPath path: KeyPath<Element, E>) -> [Element] {
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var set = Set<E>()
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return filter { set.insert($0[keyPath: path]).inserted }
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}
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}
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