Range Description

Range.md

Range

• 参考URL: Swift4 Stringのsubstring周りが変わっていた

• ClosedRange<Int>

// 1から5まで
let oneTofive = 1...5

/* Int */
let low = oneTofive.lowerBound
let upper = oneTofive.upperBound

/* ClosedRange<Int>.Index */
let startIndex = oneTofive.startIndex
let endIndex = oneTofive.endIndex

• Range<Int>

// 1から5未満
let oneTolessthanfive = 1..<5

• PartialRangeFrom<Int>

// 1以上
let morethanOne = 1...

• PartialRangeThrough<Int>

// 5以下
let lessthanFive = ...5

• PartialRangeUpTo<Int>

// 5未満
let lessthanFive = ..<5

substring

let text : String = "abcdefg"

• String.SubSequence

// 先頭〜5文字目まで
let text1 = text[text.startIndex...text.index(text.startIndex, offsetBy: 4)]
let text2 = text[text.startIndex..<text.index(text.startIndex, offsetBy: 5)]
let text3 = text[..<text.index(text.startIndex, offsetBy: 5)]

// ２文字目から末尾まで
let text1 = text[text.index(text.startIndex, offsetBy: 1)...]
let text2 = text[text.index(text.startIndex, offsetBy: 1)...text.index(before: text.endIndex)]
let text3 = text[text.index(text.startIndex, offsetBy: 1)..<text.endIndex]

// ２〜４文字目
let text1 = text[text.index(text.startIndex, offsetBy: 1)...text.index(text.startIndex, offsetBy: 3)]
let text2 = text[text.index(text.startIndex, offsetBy: 1)..<text.index(text.startIndex, offsetBy: 4)]

let from = text.index(text.startIndex, offsetBy: 1)
let to = text.index(from, offsetBy: 2)
let text3 = text[from...to]

// 先頭から5文字
let text1 = text.prefix(5)

// 末尾から3文字
let text1 = text.suffix(3)

// 末尾から2文字削る
let text1 = text.prefix(text.count - 2)

extension

extension String {
    
    func substring(_ r: CountableRange<Int>) -> String {
        
        let length = self.count
        let fromIndex = (r.startIndex > 0) ? self.index(self.startIndex, offsetBy: r.startIndex) : self.startIndex
        let toIndex = (length > r.endIndex) ? self.index(self.startIndex, offsetBy: r.endIndex) : self.endIndex
        
        if fromIndex >= self.startIndex && toIndex <= self.endIndex {
            return String(self[fromIndex..<toIndex])
        }
        
        return String(self)
    }
    
    func substring(_ r: CountableClosedRange<Int>) -> String {
        
        let from = r.lowerBound
        let to = r.upperBound
        
        return self.substring(from..<(to+1))
    }
    
    func substring(_ r: CountablePartialRangeFrom<Int>) -> String {
        
        let from = r.lowerBound
        let to = self.count
        
        return self.substring(from..<to)
    }
    
    func substring(_ r: PartialRangeThrough<Int>) -> String {
        
        let from = 0
        let to = r.upperBound
        
        return self.substring(from..<to)
    }
    
    func substring(_ r: PartialRangeUpTo<Int>) -> String {
        
        let from = 0
        let to = r.upperBound
        
        return self.substring(from..<to)
    }
}

Example

let data = "ABCD//EFGH"
let result = data.range(of: "//")

if let theRange = result{
    /* EFGH */
    print(data[theRange.upperBound...])
}