如何传递一个向量列表到clojure.jdbc / insert！封闭 [英] How to pass a list of vector to clojure.jdbc/insert! in closure

问题描述

每个以下链接 http://clojure.github.io /java.jdbc/#clojure.java.jdbc/insert ！

此函数的参数为​​

 (insert! db-spec table col-name-vec col-val-vec & col-val-vecs :transaction? true :entities identity)

因此它接受多个向量插入作为多行。

So it accept multiple vectors to be inserts as multiple rows.

但是如果我有一个向量列表，并且如何传递它到这个函数？

But if I have a list of vectors, and how to pass it to this function?

    (def rows (repeat 10 [ 1 2])) 
    (clojure.jdbc/insert mydb test_table [:a :b] rows)  ;; this doesn't work as rows is a list of vector
    ;; I could use map to insert one by one but that's slow,
    ;; so how to convert rows into multiple vector? 
    ;;I am think of apply function but don't know how to use it here.

推荐答案

我想你要使用 apply ：

(def rows (repeat 10 [ 1 2])) 
(apply clojure.jdbc/insert! mydb test_table [:a :b] rows)

apply 在您包含要作为参数传递给函数的值的集合的情况下非常有用。

In general, apply is useful in cases where you have a collection containing values you want to pass as parameters to a function.

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