困难的定义 把想法写下来的确能让自己的思路更加清晰,写成博客以后查阅也比较方便,以后得勤写。 记得以前看数学和物理发展史时,注意到一个现象,在某个概念或者 … ← Research++: what you should know about being a researcher but probably don't Do We Really Need Dataframe in Clojure? →