所以我有以下功能,当从REPL调用时效果很好:
(defn plot-data-files
"Produces a file with x-axis values on 1st column and y-axis values on the
2nd column"
[]
(let [filename (user-input "file to which you want to write plot output")
x-values file-data-days
y-values (get-dndtf)
file-writer (new java.io.FileWriter filename)]
(if (= (first y-values) za-not-found)
(println za-not-found)
(for [index (range (count x-values))]
(binding [*out* file-writer]
(prn (Double/parseDouble (str (nth x-values index)))
(Double/parseDouble (str (nth y-values index)))))))))
但是,当我尝试使用Leinigen生成jar文件时,该函数不再写入文件。所以我尝试从REPL调用-main
,果然,该函数也不会写入文件,即使它在自己调用时也是如此。所以,我尝试定义另一个函数:
(defn call-plot-function
"Basically calls the plot function, plot-data-files"
[] (plot-data-files))
果然,它有效。我再次尝试拨打-main
,但这次直接拨打call-plot-function
而不是plot-data-files
:
(defn -main [& args]
(get-all-file-data)
(while (not (= \n (first (user-input "whether you want to output more plot
files"))))
(call-plot-function)))
同样,plot-data-files
在调用-main
时不会写文件输出。我该怎么办?
答案 0 :(得分:6)
for
不是循环。你的-main
正在返回一个懒惰的序列,你永远不会强迫它的任何元素。 repl强制打印,这就是你看到差异的原因。如果您想要副作用而不是序列,doseq
具有与for
相同的语义。