R:如何将数据聚合成百分比而不丢失 ggplot2 中堆积条形图的数据？

Question

我想按位置和底物(参见下面的示例数据)将我的“核型”分子数据总结为百分比，以便在 ggplot2 中创建堆栈条形图。

我已经弄清楚如何使用“dcast”获得每种核型的总数，但无法弄清楚如何获得三种核型(即“BB”、“BD”、“DD”)中每一种的百分比.

数据的格式应能在“ggplot2”中制作堆积条形图。

示例数据:

library(reshape2)
Karotype.Data <- structure(list(Location = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L, 2L), .Label = c("Kampinge", "Kaseberga", "Molle", "Steninge"
), class = "factor"), Substrate = structure(c(1L, 1L, 1L, 1L, 
1L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 
2L, 2L, 2L, 2L, 2L), .Label = c("Kampinge", "Kaseberga", "Molle", 
"Steninge"), class = "factor"), Karyotype = structure(c(1L, 3L, 
4L, 4L, 3L, 3L, 4L, 4L, 4L, 3L, 1L, 4L, 3L, 4L, 4L, 3L, 1L, 4L, 
3L, 3L, 4L, 3L, 4L, 3L, 3L), .Label = c("", "BB", "BD", "DD"), class = "factor")), .Names = c("Location", 
"Substrate", "Karyotype"), row.names = c(135L, 136L, 137L, 138L, 
139L, 165L, 166L, 167L, 168L, 169L, 236L, 237L, 238L, 239L, 240L, 
326L, 327L, 328L, 329L, 330L, 426L, 427L, 428L, 429L, 430L), class = "data.frame")

## Summary count for each karoytype ##
Karyotype.Summary <- dcast(Karotype.Data , Location + Substrate ~ Karyotype, value.var="Karyotype", length)

Answer 1

您可以使用dplyr 包:

library(dplyr)
z.counts <- Karotype.Data %>% 
  group_by(Location,Substrate,Karyotype) %>% 
  summarize(freq=n()) 

z.freq <- z.counts %>% 
  group_by(Location,Substrate) %>% 
  mutate(freq=freq/sum(freq)*100)

这里，数据保留为长格式，因此可以直接使用 ggplot 构建条形图:

library(ggplot2)
ggplot(z.freq) + 
  aes(x=Karyotype,y=freq) + 
  facet_grid(Location~Substrate) + 
  geom_bar(stat='identity')