https://cran.r-project.org/web/packages/hash/hash.pdf

我简单看了看文档，的确跟perl里面的hash功能类似，非常好用。

创建一个hash很简单

h <- hash( keys=letters, values=1:26 )

h <- hash( letters, 1:26 )

类似于下面的列表

L=setNames(as.list(LETTERS),1:26)

如果是列表要提取keys需要用names函数，如果需要提取values，需要用unlist函数，而用了hash之后，这两个函数就可以独自运行啦

还有很多其它函数，其实在list中也可以实现，主要是看你对哪种语法更熟悉，感觉自己现在编程能力差不多算是小有所成了，看什么都一样了，要是以前学R的时候看到了这个hash包，我肯定会很兴奋的！

clear signature(x = "hash"): Remove all key-value pairs from hash
del signature(x = "ANY", hash = "hash"): Remove specified key-value pairs from hash
has.key signature(key = "ANY", hash = "hash"): Test for existence of key
is.empty signature(x = "hash"): Test if no key-values are assigned
length signature(x = "hash"): Return number of key-value pairs from the hash
keys signature(hash = "hash"): Retrieve keys from hash
values signature(x = "hash"): Retrieve values from hash
copy signature(x = "hash"): Make a copy of a hash using a new environment.
format signature(x = "hash"): Internal function for displaying hash