LINQ风格的R中的数据处理 [英] Data manipulation in R in LINQ style
本文介绍了LINQ风格的R中的数据处理的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想知道R中是否有支持C#/LINQ,F#等调用链样式数据操纵的程序包? 我想启用这样的样式:
I'm interested if there's a package in R to support call-chain style data manipulation, like in C#/LINQ, F#? I want to enable style like this:
var list = new[] {1,5,10,12,1};
var newList = list
.Where(x => x > 5)
.GroupBy(x => x%2)
.OrderBy(x => x.Key.ToString())
.Select(x => "Group: " + x.Key)
.ToArray();
推荐答案
我不知道一个,但这是它看起来像的开始:
I don't know of one, but here's the start of what it could look like:
`%then%` = function(x, body) {
x = substitute(x)
fl = as.list(substitute(body))
car = fl[[1L]]
cdr = {
if (length(fl) == 1)
list()
else
fl[-1L]
}
combined = as.call(
c(list(car, x), cdr)
)
eval(combined, parent.frame())
}
df = data.frame(x = 1:7)
df %then% subset(x > 2) %then% print
此打印
x
3 3
4 4
5 5
6 6
7 7
如果您继续使用此类骇客,那么获取此类信息应该非常简单 令人愉悦的语法;-)
If you keep using hacks like that it should be pretty simple to get the kind of syntax you find pleasing ;-)
结合plyr
,这一点都还不错:
edit: combined with plyr
, this becomes not bad at all:
(data.frame(
x = c(1, 1, 1, 2, 2, 2),
y = runif(6)
)
%then% subset(y > 0.2)
%then% ddply(.(x), summarize,
ysum = sum(y),
ycount = length(y)
)
%then% print
)
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