Programming in Swift: Functions & Types

Jan 4 2022 · Swift 5.5, iOS 15, Xcode 13

Part 2: Closures

17. filter, reduce, & sort

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Previous episode: 16. Challenge: Closures & Collections Next episode: 18. Challenge: filter & reduce

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Notes: 17. filter, reduce, & sort

More About Algorithms

Update Notes: This course was originally recorded in 2019. It has been reviewed and all content and materials updated as of October 2021.

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This is the last episode that will focus on using closures and collections together, and here, we’ll tackle filter, reduce, and the sort methods.

dwarves.filter(<#T##isIncluded: (String) throws -> Bool##(String) throws -> Bool#>)  

  dwarves.filter { (<#String#>) -> Bool in
    <#code#>
  }

  dwarves.filter { (😺dwarf🛑) -> Bool in

    dwarf > "M"

  dwarves.filter { ❌(dwarf) -> Bool in❌
    dwarf > "M"
  }

dwarves.filter { $0 > "M" }

  var totalGrade = ❌0
  for grade in grades {
    totalGrade += grade
  }❌

var totalGrade = 😺grades.reduce(<#T##initialResult: Result##Result#>, <#T##nextPartialResult: (Result, Int) throws -> Result##(Result, Int) throws -> Result#>)

grades.reduce(😺0🛑) { 

}

let totalGrade = grades.reduce(0) { (<#Result#>, <#Int#>) -> Result in
    <#code#>
  }

grades.reduce(0) { 😺total, grade🛑 -> Result

grades.reduce(0) { total, grade -> 😺Int🛑 in

  total + grade

getPassStatus(for: ozmaGrades, lowestPass: 60)

  let totalGrade = grades.reduce(0, 😺+) //{ total, grade -> Int in
//    total + grade
//  }🛑

let stockSums = 

let stockSums = stock.reduce(into: <#T##Result#>, <#T##updateAccumulatingResult: (inout Result, (key: Double, value: Int)) throws -> ()##(inout Result, (key: Double, value: Int)) throws -> ()#>)

let stockSums = stock.reduce(into: 😺[]) { (<#inout Result#>, <#(key: Double, value: Int)#>) in
  <#code#>
}

let stockSums = stock.reduce(into: []) { (😺result, item🛑) in

  result.append(item.key * Double(item.value))

names.sort()

names.sort { (a, b) -> Bool in

}

  a > b
}
names

names.sort(by: >)

let longToShortNames = names.sorted {
  
}

let longToShortNames = names.sorted {
  $0.count > $1.count
}

longToShortNames
names

  dwarves.filter { $0 > "M" }
}.sorted()