从Haskell文件中读取

Question

从文件中读取这些行并制作一个这样的列表

 2010‐04‐16,130.68,132.17,130.25,130.63,9546200,130.63
 2010‐04‐15,130.53,131.14,130.19,130.89,6425300,130.89   

List [ "2010‐04‐16","130.68,132.17","130.25","130.63","9546200","130.63"]

我怎么能用take谓词做这个？或任何其他谓词

Answer 1

我可以使用Data.List API执行类似的操作：

import Data.List

split :: Eq a => a -> [a] -> [[a]]
split delim = map (dropWhile (== delim)) . groupBy (\_ c -> c /= delim)

带有一个输入字符串的输出将是：

Prelude Data.List> split ',' "20100416,130.68,132.17,130.25,130.63,9546200,130.63"
["20100416","130.68","132.17","130.25","130.63","9546200","130.63"]

... HTH