![](https://2.bp.blogspot.com/-kkTCjS8lskU/VX_VwaBGlSI/AAAAAAAAUQM/r5aktgSXkzs/s640/map_filter_reduce.png)
- map_filter_reduce.swift Select all
let words = ["angry", "hungry", "aardvark", "aardwolf"]
func concatenate(xs: [String]) -> String {
var result: String = ""
for x in xs {
result += x + " "
}
return result.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
}
concatenate(words)
// "angry hungry aardvark aardwolf"
println("GRR!! " + words
.filter {$0.hasSuffix("gry")}
.map {$0.uppercaseString}
.reduce("HULK") {"\($0) \($1)"} + "!!!"
)
// "GRR!! HULK ANGRY HUNGRY!!!"
let numbers = [ 10000, 10303, 30913, 50000, 100000, 101039, 1000000 ]
println( numbers
.filter { $0 % 2 == 0 }
.map { NSNumberFormatter.localizedStringFromNumber($0, numberStyle: .DecimalStyle) }
.reduce("") { countElements($0) == 0 ? $1 : $0 + " " + $1 }
)
// "10,000 50,000 100,000 1,000
Updated for Swift 3.0 syntax below
- map_filter_reduce.swift Select all
let words = ["angry", "hungry", "aardvark", "aardwolf"]
func concatenate(_ xs: [String]) -> String {
var result: String = ""
for x in xs {
result += x + " "
}
return result.trimmingCharacters(in: .whitespaces) // Xcode 8 beta 6
// return result.trimmingCharacters(in: NSCharacterSet.whitespaces()) // Xcode 8 beta 1
}
concatenate(words)
// "angry hungry aardvark aardwolf"
print("GRR!! " + words
.filter {$0.hasSuffix("gry")}
.map {$0.uppercased()}
.reduce("HULK") {"\($0) \($1)"} + "!!!"
)
// "GRR!! HULK ANGRY HUNGRY!!!"
let numbers = [ 10000, 10303, 30913, 50000, 100000, 101039, 1000000 ]
print( numbers
.filter { $0 % 2 == 0 }
.map { NumberFormatter.localizedString(from: ($0 as NSNumber) , number: .decimal) } // Xcode 8 beta 6
// .map { NumberFormatter.localizedString(from: $0, number: .decimal) } //Xcode 8 beta 1
.reduce("") { $0.characters.count == 0 ? $1 : $0 + " " + $1 }
)
// "10,000 50,000 100,000 1,000
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