Python的KeyError的惯用Clojure版本

这个python应该如何表达

gl_enums = ... # map from name to values for opengl enums
# use with gl_enums["enum name"]

在clojure？这可行,但是对吗？

(def gl-enums ...) ; map from name to values for opengl enums
(defn gl-enum [k] (or (gl-enums k) (throw (SomeException.))))
; use with (gl-enum :enum-name)

编辑：为澄清起见,此问题与引发异常的部分有关,而不是与地图定义的部分有关

解决方法:

您最初的示例是可以的.您也可能会遇到两种方法：

;; not very idiomatic
(defn example
  [m]
  (if (contains? m :name)
    (:name m)
    (throw (IllegalArgumentException. (format "key %s is missing" :name)))))

;; idiomatic
(defn example
  [m]
  (if-let [v (:name m)]
    v
    (throw (IllegalArgumentException. (format "key %s is missing" :name)))))

More on clojure.core/if-let
More on clojure.core/contains?

标签：clojure,idioms,python
来源： https://codeday.me/bug/20191201/2080356.html