摘要：
在学习haskell 记录以下常用的函数随时更新！spanspan:: (a ->Bool) -> [a] -> ([a], [a])span, applied to a predicatepand a listxs, returns a tuple where first element is longest prefix (possibly empty) ofxsof elements that satisfypand second element is the remainder of the list:接受一个 判断条件 和 一个 list xs, 返回一个包含两个l 阅读全文
