如何将数据帧转换为行和列中具有组值的矩阵? [英] How to transform a data frame into a matrix with group values in rows and columns?

问题描述

我运行了一段这样的代码

I ran a piece of code like this

x = data.frame(numerator = 1:3, value = letters[1:3],value1=letters[4:6])
xa = aggregate(list(x$numerator),by=list(x$value,x$value1),FUN=sum)

但是结果xa的格式如下

 Group.1 Group.2 X1.3
1       a       d    1
2       b       e    2
3       c       f    3

我希望我的结果以矩阵格式进行组织，以使行由Group.1值表示，而列由Group.2值表示，如下所示:

I would like my results to be organised in a matrix format such that the rows are represented by the Group.1 values and the columns are represented by the Group.2 values, like the following:

    d e f
a   1 NULL NULL
b   NULL 2 NULL
c   NULL NULL 3

我该怎么做?

推荐答案

您可以从plyr包中使用daply.

You can use daply from plyr package.

xa = daply(.data=x,
           .variables=c("value","value1"),
           .fun=function(x) sum(x$numerator))

这篇关于如何将数据帧转换为行和列中具有组值的矩阵?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！