Why is it so hard to find examples of Swift dictionary reduce operations? Examples for arrays abound :
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let countme = [1, 2, 3, 4, 5] let sumall = countme.reduce(0){$0+$1} // sumall is now 15 |
See this if you’re looking for a detailed HowTo.
But dictionary is the more advanced problem. How do I reduce when I have keys and values?
The key here is to note that a dictionary yields the contents of its sequence in tuples containing pairs of values. We still have our familiar $0, $1 arguments from reduce as above, where $0 is the partial sum and $1 is the individual element value. But now $0 and $1 are both tuples, and you get to their contents through $0.0, $0.1, $1.0, and $1.1.
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let namesNumbers = ["Mike":21, "Bruce":25, "Alice":27] let (bigname,bignumber) = namesNumbers.reduce(("",0)) {return ($0.0 + $1.0, $0.1 + $1.1)} |
This example concatenates the strings and adds the integers, and the two separate data types just happen to use the same symbol for the two operations.
