[swift-users] How to merge two dictionaries?

[Jens Alfke]

> On Nov 11, 2016, at 12:14 AM, Ray Fix via swift-users <swift-users at swift.org> wrote:
> 
> The reason I don’t think it is provided is because it is difficult to know what to do when keys collide.

When you add a single entry to a dictionary with []=, it simply replaces any existing value. I would expect adding multiple entries to do the same. (Which is what NSDictionary’s -addEntries: method does.)

Sure, there are different policies you could want, like ignoring duplicate keys or somehow combining the values, but replacing is a common default. It seems wrong not to have this method just because there’s more than one way it could work. (“Don’t let the best be the enemy of the good.”)

—Jens
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