如何重命名plyr的** ply函数的输出行/列? [英] How can I rename the output rows/cols of **ply functions from plyr?

问题描述

我想在plyr包的**ply函数ldply中声明行/列的输出名称.

I would like to state the row/col output names in a **ply function, ldply, from the plyr package.

例如

我有一个列表foo，我想将其转换为data.frame并用signif()截断有效数字

I have a list, foo, that I want to convert to a data.frame and truncate significant digits with signif()

 foo <- list(var.a = runif(3), var.b = runif(3), var.c=runif(3))

我现在拥有的是

q <- ldply(foo, signif, 2)
colnames(dq)[1] <- c('id', 'q1', 'q2','q3')
rownames(dq) <- dq$id

有没有更简单的方法?

之前的两个问题询问了如何使用plyr重命名行和 cols ，并使用plyr，但我认为我的问题有所不同.名称可以与另一个功能同时声明(或者如果我正确执行的话)吗?这是一个有价值的功能请求吗?

Two previous questions have asked how to use plyr to rename rows and cols using plyr, but I think my question is different. Can the names be stated at the same time as another function (or if I am doing this correctly)? Is this a worthwhile feature request?

推荐答案

您必须在某个地方给出名称，例如在内部调用的函数上，例如

You have to give names somewhere, either on the function being called inside as eg in

R> ldply(foo, function(l) c(a=signif(l[1], 2), b=signif(l[2], 2), 
+                           c=signif(l[3], 2)))
    .id    a    b    c
1 var.a 0.50 0.72 0.27
2 var.b 0.82 0.38 0.24
3 var.c 0.13 0.27 0.81
R> 

或者您在通话后做了什么.

or has you did after the call.

我经常使用的另一个选项是在匿名工作程序函数中显式创建单行data.frame.然后*dply()等将它们简单地整理为一个data.frame.这足以满足我的口味.

Another option I frequently use is to explicitly create one-row data.frame in the anonymous worker function. *dply() et al then simply collated these into a single data.frame. That works well enough for my tastes.

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