Does joinWithSeparator exist for attribute strings

Question

An array of strings can be combined with a specific separator using the joinWithSeparator method.

let st = [ "apple", "pie", "potato" ]
st.joinWithSeparator(", ")

As a result, we will have an "apple, pie, potato."

What if I bind strings in my array? Is there an easy way to combine them into one large anchored string?

Answer 1

Catch:

import Foundation

extension SequenceType where Generator.Element: NSAttributedString {
    func joinWithSeparator(separator: NSAttributedString) -> NSAttributedString {
        var isFirst = true
        return self.reduce(NSMutableAttributedString()) {
            (r, e) in
            if isFirst {
                isFirst = false
            } else {
                r.appendAttributedString(separator)
            }
            r.appendAttributedString(e)
            return r
        }
    }

    func joinWithSeparator(separator: String) -> NSAttributedString {
        return joinWithSeparator(NSAttributedString(string: separator))
    }
}

Answer 2

For Swift 3.0, the sequence type was not supported when I switch to Array. I also change the method name to use swift 3.0 style

extension Array where Element: NSAttributedString {
    func joined(separator: NSAttributedString) -> NSAttributedString {
        var isFirst = true
        return self.reduce(NSMutableAttributedString()) {
            (r, e) in
            if isFirst {
                isFirst = false
            } else {
                r.append(separator)
            }
            r.append(e)
            return r
        }
    }

    func joined(separator: String) -> NSAttributedString {
        return joined(separator: NSAttributedString(string: separator))
    }
}

Answer 3

Swift 4, Sequence:

extension Sequence where Iterator.Element: NSAttributedString {
    /// Returns a new attributed string by concatenating the elements of the sequence, adding the given separator between each element.
    /// - parameters:
    ///     - separator: A string to insert between each of the elements in this sequence. The default separator is an empty string.
    func joined(separator: NSAttributedString = NSAttributedString(string: "")) -> NSAttributedString {
        var isFirst = true
        return self.reduce(NSMutableAttributedString()) {
            (r, e) in
            if isFirst {
                isFirst = false
            } else {
                r.append(separator)
            }
            r.append(e)
            return r
        }
    }

    /// Returns a new attributed string by concatenating the elements of the sequence, adding the given separator between each element.
    /// - parameters:
    ///     - separator: A string to insert between each of the elements in this sequence. The default separator is an empty string.
    func joined(separator: String = "") -> NSAttributedString {
        return joined(separator: NSAttributedString(string: separator))
    }
}