内连接clojure [英] Inner-join in clojure

问题描述

假设我有

(def test-left 
                            [{:name "Sean" :age 27} 
                             {:name "Ross" :age 27} 
                             {:name "Brian" :age 22}])

和

(def test-right 
                        [{:owner "Sean" :item "Beer"} 
                         {:owner "Sean" :item "Pizza"} 
                         {:owner "Ross" :item "Computer"} 
                         {:owner "Matt" :item "Bike"}])

当我做一个（clojure.set / join test-left test-right）我得到一个笛卡尔积。 12行。我想要的是inner-join on：left =：right的所有者，所以我只得到那些在右侧有匹配行的结果

When I do a (clojure.set/join test-left test-right) I get a Cartesian product. 12 rows. What I want is Inner-join on :name of left = :owner of right so that I get only those result which have matching rows in the right side

              [{:name "Sean" :age 27  :item "Beer" } 
               {:name "Sean" :age 27  :item "Pizza" }
               {:name "Ross" :age 27  :item "Computer"}]

任何想法。同样想实现左和右外部联接，但这是separete问题。我正在学习clojure，请与我一起。

Any Ideas. Similarly Would like to achieve left and right outer joins but that is separete question. I am learning clojure so please bear with me

推荐答案

我的错误

1:24 main-hta=> (clojure.set/join test-left test-right {:name :owner})

gets

#{{:item "Pizza", :owner "Sean", :name "Sean", :age 27} {:item "Beer", :owner "Sean", :name "Sean", :age 27} {:item "Computer", :owner "Ross", :name "Ross", :ag
e 27}}

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