Why does Clojure have “keywords” in addition to “symbols”?

Question

I have a passing knowledge of other Lisps (particularly Scheme) from way back. Recently I\'ve been reading about Clojure. I see that it has both \"symbols\" and \"keywords\"

Answer 1

:keywords are also treated specially by many of the collections, allowing for some really convenient syntax.

(:user-id (get-users-map))

is the same as

((get-users-map) :user-id)

this makes things just a little more flexable