将使用“by”创建的摘要转换为data.frame [英] converting summary created using 'by' to data.frame

问题描述

df1=data.frame(c(2,1,2),c(1,2,3,4,5,6),seq(141,170)) #create data.frame
names(df1) = c("gender","age","height") #column names
df1$gender <- factor(df1$gender,
levels=c(1,2),
labels=c("female","male")) #gives levels and labels to gender
df1$age <- factor(df1$age,
levels=c(1,2,3,4,5,6),
labels=c("16-24","25-34","35-44","45-54","55-64","65+")) # gives levels and labels to age groups

我我正在寻找一个由性别，然后年龄分组的高度值的摘要。

I am looking to produce a summary of the height values subsetted by gender and then age.

使用子集和 by 函数提供我想要的输出：

Using the subset and by functions as provides the output I want:

females<-subset(df1,df1$gender==1) #subsetting by gender
males<-subset(df1,df1$gender==2)

foutput=by(females$height,females$age,summary) #producing summary subsetted by age
moutput=by(males$height,males$age,summary)

但是我要求它是我n一个数据框架，以便我可以使用XLconnect将这些结果与频率表一起导出。

However I require it to be in a data.frame so that I can export these results alongside frequency tables using XLconnect.

有没有办法将输出转换为data.frame或优雅的选择，可能使用plyr？

Is there an way to convert the output to a data.frame or an elegant alternative, possibly using plyr?

推荐答案

这是使用plyr的一种方法：

Here's one approach using plyr:

> ddply(df1, c("gender", "age"), function(x) summary(x$height))
  gender   age Min. 1st Qu. Median Mean 3rd Qu. Max.
1 female 25-34  142     148    154  154     160  166
2 female 55-64  145     151    157  157     163  169
3   male 16-24  141     147    153  153     159  165
4   male 35-44  143     149    155  155     161  167
5   male 45-54  144     150    156  156     162  168
6   male   65+  146     152    158  158     164  170

这篇关于将使用“by”创建的摘要转换为data.frame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！