r - 计算ggplot中值的出现次数

Question

我有以下数据:

df = data.frame(c("2012","2012","2012","2013"),
                c("tuesday","tuesday","friday","thursday"),
                c("AAA","BBB","AAA","AAA"))
colnames(df) = c("year","day","type")

我想显示每年和每天 type 值(AAA、BBB)的出现次数(绝对频率)。目前我写了下面的代码，但是它要求我在aes中增加一个维度，例如aes(type, some_dimension, fill = as.factor(year))。那么，如何添加类似count(type) 的内容？

ggplot(dat) +
  geom_bar(aes(type, fill = as.factor(year)), 
           position = "dodge", stat = "identity") + 
  facet_wrap(~day)

Answer 1

在 geom_bar 中，将 stat 从 "identity" 更改为 "count"，如下所示:

library("ggplot2")

ggplot(df) +
    geom_bar(aes(x = type, fill = as.factor(year)), 
             position = "dodge", stat = "count") + 
    facet_wrap(~day)