2015-02-11 8:32 GMT+01:00 Cecil Westerhof <cldwester...@gmail.com>:
>
> I needed a function to get the percentage as an int. Input is place and
> total-count.
> I want the normal definition (which is the default) and a high and low
> variant.
>
> I came up with the following code:
> (defn get-percentage
> ([place total-count] (get-percentage :normal place total-count))
> ([mode place total-count]
> (let [percentage
>
> (/ (* place 100.0) total-count)]
> (condp = mode
> :high (int (Math/ceil percentage))
> :low (int (Math/floor percentage))
> :normal (int (Math/round percentage))
> (throw (Exception. "ERROR: get-percentage [:high|:low|:normal]
> <PLACE> <TOTAL_COUNT>"))))))
>
> Is this a good version, or could it be done better?
>
Everyone thanks for the comments. I did the following.
I made three round functions:
(defn round [x] (int (Math/round x)))
(defn round-high [x] (int (Math/ceil x)))
(defn round-low [x] (int (Math/floor x)))
And rewrote get-percentage to:
(defn get-percentage
([place total-count] (get-percentage :normal place total-count))
([mode place total-count]
(let [mode-fn (case mode
:high round-high
:low round-low
:normal round
(throw (Exception.
"ERROR: get-percentage [:high|:low|:normal]
<PLACE> <TOTAL_COUNT>")))]
(-> place (* 100.0) (/ total-count) mode-fn int))))
But I wanted to do it a little neater.
I wrote a new round function:
(defn round
([x] (round :normal x))
([mode x]
(println mode)
(println x)
(case mode
:high (Math/ceil x)
:low (Math/floor x)
:normal (Math/round x)
(throw (Exception.
"ERROR: round [:high|:low|:normal] <VALUE>")))))
Then I tried to rewrite get-percentage:
(defn get-percentage
([place total-count] (get-percentage :normal place total-count))
([mode place total-count]
(if-not (contains? #{:high :low :normal} mode)
(throw (Exception.
"ERROR: get-percentage [:high|:low|:normal] <PLACE>
<TOTAL_COUNT>")))
(round mode (/ (* place 100.0) total-count))))
But this gives on the last line:
CompilerException java.lang.RuntimeException: Unable to resolve symbol:
in this context,
When I put before that statement:
(println mode)
(println place)
(println total-count)
(println (/ place total-count))
(println (/ (* place 100.0) total-count))
I get the same error on:
(println (/ place total-count))
What is happening here?
I am using Clojure 1.6.0 on Linux.
--
Cecil Westerhof
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