将比例表扩展到百分比（百分比） [英] Extend contigency table with proportions (percentages)

问题描述

我有一个列联表，我想用每组的相应比例扩展它。

I have a contingency table of counts, and I want to extend it with corresponding proportions of each group.

一些样本数据（提示来自 ggplot2 包的数据集）：

Some sample data (tips data set from ggplot2 package):

library(ggplot2)

head(tips, 3)
#   total_bill tip    sex smoker day   time size
# 1         17 1.0 Female     No Sun Dinner    2
# 2         10 1.7   Male     No Sun Dinner    3
# 3         21 3.5   Male     No Sun Dinner    3

首先，使用表计算吸烟者与非吸烟者，并 nrow 计算对象总数：

First, use table to count smoker vs non-smoker, and nrow to count total number of subjects:

table(tips$smoker)
#  No Yes 
# 151  93 

nrow(tips)
# [1] 244

然后，我想计算吸烟者与非吸烟者的百分比。像这样（难看的代码）：

Then, I want to calculate percentage of smokers vs. non smokers. Something like this (ugly code):

# percentage of smokers
options(digits = 2)

transform(as.data.frame(table(tips$smoker)), percentage_column = Freq / nrow(tips) * 100)
#   Var1 Freq percentage_column
# 1   No  151                62
# 2  Yes   93                38

是否有更好的方法？

（甚至更好的方法是在一组列（我列举）上执行此操作，并以某种格式正确地输出）
（例如，吸烟者，日期和时间）

(even better it would be to do this on a set of columns (which I enumerate) and have output somewhat nicely formatted) (e.g., smoker, day, and time)

推荐答案

如果您所追求的简洁，您可能会喜欢：

If it's conciseness you're after, you might like:

prop.table(table(tips$smoker))

然后根据需要缩放100并四舍五入。或更像是您的确切输出：

and then scale by 100 and round if you like. Or more like your exact output:

tbl <- table(tips$smoker)
cbind(tbl,prop.table(tbl))

如果要对多个列执行此操作，则会有很多不同可以根据自己的口味告诉您的方向，输出看起来很干净，但这是一个选择：

If you wanted to do this for multiple columns, there are lots of different directions you could go depending on what your tastes tell you is clean looking output, but here's one option:

tblFun <- function(x){
    tbl <- table(x)
    res <- cbind(tbl,round(prop.table(tbl)*100,2))
    colnames(res) <- c('Count','Percentage')
    res
}

do.call(rbind,lapply(tips[3:6],tblFun))
       Count Percentage
Female    87      35.66
Male     157      64.34
No       151      61.89
Yes       93      38.11
Fri       19       7.79
Sat       87      35.66
Sun       76      31.15
Thur      62      25.41
Dinner   176      72.13
Lunch     68      27.87

如果您不喜欢堆叠其他表s彼此重叠，则可以放弃 do.call 并将它们保留在列表中。

If you don't like stack the different tables on top of each other, you can ditch the do.call and leave them in a list.

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