//
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// RangeReplaceableCollectionExtensions.swift
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// SwifterSwift
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//
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// Created by Luciano Almeida on 7/2/18.
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// Copyright © 2018 SwifterSwift
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//
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// MARK: - Initializers
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public extension RangeReplaceableCollection {
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/// SwifterSwift: Creates a new collection of a given size where for each position of the collection the value will be the result of a call of the given expression.
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///
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/// let values = Array(expression: "Value", count: 3)
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/// print(values)
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/// // Prints "["Value", "Value", "Value"]"
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///
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/// - Parameters:
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/// - expression: The expression to execute for each position of the collection.
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/// - count: The count of the collection.
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init(expression: @autoclosure () throws -> Element, count: Int) rethrows {
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self.init()
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// swiftlint:disable:next empty_count
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if count > 0 {
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reserveCapacity(count)
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while self.count < count {
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append(try expression())
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}
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}
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}
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}
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// MARK: - Methods
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public extension RangeReplaceableCollection {
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/// SwifterSwift: Returns a new rotated collection by the given places.
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///
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/// [1, 2, 3, 4].rotated(by: 1) -> [4,1,2,3]
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/// [1, 2, 3, 4].rotated(by: 3) -> [2,3,4,1]
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/// [1, 2, 3, 4].rotated(by: -1) -> [2,3,4,1]
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///
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/// - Parameter places: Number of places that the array be rotated. If the value is positive the end becomes the start, if it negative it's that start becom the end.
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/// - Returns: The new rotated collection.
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func rotated(by places: Int) -> Self {
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// Inspired by: https://ruby-doc.org/core-2.2.0/Array.html#method-i-rotate
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var copy = self
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return copy.rotate(by: places)
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}
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/// SwifterSwift: Rotate the collection by the given places.
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///
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/// [1, 2, 3, 4].rotate(by: 1) -> [4,1,2,3]
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/// [1, 2, 3, 4].rotate(by: 3) -> [2,3,4,1]
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/// [1, 2, 3, 4].rotated(by: -1) -> [2,3,4,1]
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///
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/// - Parameter places: The number of places that the array should be rotated. If the value is positive the end becomes the start, if it negative it's that start become the end.
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/// - Returns: self after rotating.
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@discardableResult
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mutating func rotate(by places: Int) -> Self {
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guard places != 0 else { return self }
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let placesToMove = places%count
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if placesToMove > 0 {
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let range = index(endIndex, offsetBy: -placesToMove)...
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let slice = self[range]
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removeSubrange(range)
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insert(contentsOf: slice, at: startIndex)
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} else {
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let range = startIndex..<index(startIndex, offsetBy: -placesToMove)
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let slice = self[range]
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removeSubrange(range)
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append(contentsOf: slice)
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}
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return self
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}
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/// SwifterSwift: Removes the first element of the collection which satisfies the given predicate.
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///
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/// [1, 2, 2, 3, 4, 2, 5].removeFirst { $0 % 2 == 0 } -> [1, 2, 3, 4, 2, 5]
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/// ["h", "e", "l", "l", "o"].removeFirst { $0 == "e" } -> ["h", "l", "l", "o"]
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///
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/// - Parameter predicate: A closure that takes an element as its argument and returns a Boolean value that indicates whether the passed element represents a match.
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/// - Returns: The first element for which predicate returns true, after removing it. If no elements in the collection satisfy the given predicate, returns `nil`.
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@discardableResult
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mutating func removeFirst(where predicate: (Element) throws -> Bool) rethrows -> Element? {
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guard let index = try firstIndex(where: predicate) else { return nil }
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return remove(at: index)
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}
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/// SwifterSwift: Remove a random value from the collection.
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@discardableResult
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mutating func removeRandomElement() -> Element? {
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guard let randomIndex = indices.randomElement() else { return nil }
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return remove(at: randomIndex)
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}
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/// SwifterSwift: Keep elements of Array while condition is true.
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///
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/// [0, 2, 4, 7].keep(while: { $0 % 2 == 0 }) -> [0, 2, 4]
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///
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/// - Parameter condition: condition to evaluate each element against.
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/// - Returns: self after applying provided condition.
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/// - Throws: provided condition exception.
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@discardableResult
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mutating func keep(while condition: (Element) throws -> Bool) rethrows -> Self {
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if let idx = try firstIndex(where: { try !condition($0) }) {
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removeSubrange(idx...)
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}
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return self
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}
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/// SwifterSwift: Take element of Array while condition is true.
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///
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/// [0, 2, 4, 7, 6, 8].take( where: {$0 % 2 == 0}) -> [0, 2, 4]
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///
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/// - Parameter condition: condition to evaluate each element against.
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/// - Returns: All elements up until condition evaluates to false.
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func take(while condition: (Element) throws -> Bool) rethrows -> Self {
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return Self(try prefix(while: condition))
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}
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/// SwifterSwift: Skip elements of Array while condition is true.
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///
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/// [0, 2, 4, 7, 6, 8].skip( where: {$0 % 2 == 0}) -> [6, 8]
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///
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/// - Parameter condition: condition to evaluate each element against.
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/// - Returns: All elements after the condition evaluates to false.
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func skip(while condition: (Element) throws-> Bool) rethrows -> Self {
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guard let idx = try firstIndex(where: { try !condition($0) }) else { return Self() }
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return Self(self[idx...])
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}
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/// SwifterSwift: Remove all duplicate elements 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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mutating func removeDuplicates<E: Equatable>(keyPath path: KeyPath<Element, E>) {
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var items = [Element]()
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removeAll { element -> Bool in
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guard items.contains(where: { $0[keyPath: path] == element[keyPath: path] }) else {
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items.append(element)
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return false
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}
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return true
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}
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}
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/// SwifterSwift: Remove all duplicate elements 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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mutating func removeDuplicates<E: Hashable>(keyPath path: KeyPath<Element, E>) {
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var set = Set<E>()
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removeAll { !set.insert($0[keyPath: path]).inserted }
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}
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}
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