按组计算的聚合和百分比

Question

我按班级R学生每周津贴数据集,如下所示:

Year    ID  Class       Allowance
2013    123 Freshman    100
2013    234 Freshman    110
2013    345 Sophomore   150
2013    456 Sophomore   200
2013    567 Junior      250
2014    678 Junior      100
2014    789 Junior      230
2014    890 Freshman    110
2014    891 Freshman    250
2014    892 Sophomore   220

如何按组(年/班)汇总结果以获得总和和%(按组)？获得总和似乎很容易,ddply因为无法获得%by group part.

它适用于sum:

summary <- ddply(my_data, .(Year, Class), summarize, Sum_Allow=sum(Allowance))

但它不适用于按部分分组的百分比:

summary <- ddply(my_data, .(Year, Class), summarize, Sum_Allow=sum(Allowance),
                 Allow_Pct=Allowance/sum(Allowance))

理想的结果应如下所示:

 Year     Class Sum_Allow Allow_Pct
 2013  Freshman       210       26%
 2013    Junior       250       31%
 2013 Sophomore       350       43%
 2014  Freshman       360       40%
 2014    Junior       330       36%
 2014 Sophomore       220       24%

我尝试了plyr软件包中的ddply,但是请告诉我这可能有用的方法.

Answer 1

这是使用data.table包的可能解决方案(假设您的数据被调用df)

library(data.table)
setDT(df)[, list(Sum_Allow = sum(Allowance)), keyby = list(Year, Class)][, 
            Allow_Pct := paste0(round(Sum_Allow/sum(Sum_Allow), 2)*100, "%"), by = Year][]

#    Year     Class Sum_Allow Allow_Pct
# 1: 2013  Freshman       210       26%
# 2: 2013    Junior       250       31%
# 3: 2013 Sophomore       350       43%
# 4: 2014  Freshman       360       40%
# 5: 2014    Junior       330       36%
# 6: 2014 Sophomore       220       24%

贡献给@rawr,这是一个可能的基础R解决方案

df2 <- aggregate(Allowance ~  Class + Year, df, sum)
transform(df2, Allow_pct = ave(Allowance, Year, FUN = function(x) paste0(round(x/sum(x), 2)*100, "%")))
#       Class Year Allowance Allow_pct
# 1  Freshman 2013       210       26%
# 2    Junior 2013       250       31%
# 3 Sophomore 2013       350       43%
# 4  Freshman 2014       360       40%
# 5    Junior 2014       330       36%
# 6 Sophomore 2014       220       24%

Answer 2

您可以分两步完成此操作

my_data <- read.table(header = TRUE,
                      text = "Year    ID  Class       Allowance
2013    123 Freshman    100
2013    234 Freshman    110
2013    345 Sophomore   150
2013    456 Sophomore   200
2013    567 Junior      250
2014    678 Junior      100
2014    789 Junior      230
2014    890 Freshman    110
2014    891 Freshman    250
2014    892 Sophomore   220")

library(plyr)
(summ <- ddply(my_data, .(Year, Class), summarize, Sum_Allow=sum(Allowance)))

#   Year     Class Sum_Allow
# 1 2013  Freshman       210
# 2 2013    Junior       250
# 3 2013 Sophomore       350
# 4 2014  Freshman       360
# 5 2014    Junior       330
# 6 2014 Sophomore       220

ddply(summ, .(Year), mutate, Allow_pct = Sum_Allow / sum(Sum_Allow) * 100)

#   Year     Class Sum_Allow Allow_pct
# 1 2013  Freshman       210  25.92593
# 2 2013    Junior       250  30.86420
# 3 2013 Sophomore       350  43.20988
# 4 2014  Freshman       360  39.56044
# 5 2014    Junior       330  36.26374
# 6 2014 Sophomore       220  24.17582

我不知道其他人是否也会遇到这种情况，但是当我运行最初的尝试时，R 崩溃了而不是抛出警告。或者，如果我拼错了“Allow”而不是“allow”，它就会崩溃。我真的很讨厌这样；哈德利请修复

永远的基础R