Swift find all occurrences of a substring

Question

I have an extension here of the String class in Swift that returns the index of the first letter of a given substring.

Can anybody please help me make it so it will

Answer 1

Please check the following answer for finding multiple items in multiple locations

func indicesOf(string: String) -> [Int] {
    var indices = [Int]()
    var searchStartIndex = self.startIndex
    
    while searchStartIndex < self.endIndex,
        let range = self.range(of: string, range: searchStartIndex..<self.endIndex),
        !range.isEmpty
    {
        let index = distance(from: self.startIndex, to: range.lowerBound)
        indices.append(index)
        searchStartIndex = range.upperBound
    }
    
    return indices
}

func attributedStringWithColor(_ strings: [String], color: UIColor, characterSpacing: UInt? = nil) -> NSAttributedString {
    let attributedString = NSMutableAttributedString(string: self)
    for string in strings {
        let indexes = self.indicesOf(string: string)
        for index in indexes {
            let range = NSRange(location: index, length: string.count)
            attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: color, range: range)
        }
    }
    
    guard let characterSpacing = characterSpacing else {return attributedString}
    
    attributedString.addAttribute(NSAttributedString.Key.kern, value: characterSpacing, range: NSRange(location: 0, length: attributedString.length))
    
    return attributedString
}

can be used as follows :

let message = "Item 1 + Item 2 + Item 3"
message.attributedStringWithColor(["Item", "+"], color: UIColor.red)

and gets the result