在count = 0的情况下,如何使用geom_bar()去除ggplot2图的较宽条

这是我的data.frame():

df <- data.frame(Round = rep(c("A", "B", "C" ),150), Group = rep(c("UP", "DOWN"),75),Task = rep(c("T1", "T2", "T3", "T4", "T5"),30), V2 = sample(c(0,1,2), 50, replace = T), V1 = sample(c(0,1,2), 50, replace = T))
dfmelt <- melt(df)

我想尝试这样的情节facet_grid:

b <- ggplot(data=dfmelt, aes(x=value, fill=variable))
b <- b + geom_bar(stat="count", position = "dodge", width = 0.9)
b <- b + facet_grid(Group ~ Task, scales = "free")

,产生以下内容:

我想摆脱更广泛的列,例如V1 at the position 0 of T1-UP,V1 at the position 1 of T5-DOWN和V2 at the position 0 of T3-UP.

当count给定x位置(0,1或2)中的一个变量(假设为V1)等于0且另一个变量(V2)大于时,会出现问题0.在这种情况下,V2条变宽以填充整个x位置.

我曾尝试这个和这个解决方案没有成功.有没有办法让条形有一个固定的宽度？

一种选择是在外面手动实现计数ggplot,并使用NA填充缺失数据,tidyr::complete然后执行标识栏图:

library(dplyr); library(tidyr); library(ggplot2)
dfmelt_count <- dfmelt %>% 
        count(Group, Task, variable, value) %>% 
        complete(Group, Task, variable, value)

b <- ggplot(data=dfmelt_count, aes(x=value, y = n, fill=variable))
b <- b + geom_bar(stat="identity", position = "dodge", width = 0.9)
b <- b + facet_grid(Group ~ Task, scales = "free")
b