Concatenate dictionary values in Swift

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The key-value pairs in a Dictionary are unordered. If you want to access them in a certain order, you must sort the keys yourself:

let dict = ["A": 1, "B": 2,"C": 3,"D": 4]

let str = dict.keys
            .sorted(by: <)
            .map { dict[$0]! }
            .reduce ("") { $0 + String($1) }

Or alternatively:

let str = dict.keys
            .sorted(by: <)
            .map { String(dict[$0]!) }
            .joined()

No idea about the relative performance of the two as I haven’t benchmarked them. But unless your dictionary is huge, the difference will be minimal.

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