[swift-users] Mapping a Dictionary to a Dictionary?

Jens Alfke jens at mooseyard.com
Wed Aug 31 15:47:32 CDT 2016


That’s going to be quite slow, like O(n^2), since it copies the dictionary every time it adds a key to it.
It also seems more complicated than the simple for-loop implementation; but then, I’m not a functional-language programmer.

// here’s how I’d do it; not tested in a playground
var dict2 = [Key:Value](minCapacity: dict1.count)
for (k,v) in dict1 {
	let (k1,v1) = xform(k,v)
	dict2[k1] = v1
}

—Jens
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