您可以使用离散比例删除ggplot中轴和数据之间的空间吗

debugcn 发表于 Dev

杰马克

是否可以使用离散比例减小ggplot（点）中轴和数据之间的空间。我已经看到了许多使用离散比例尺进行此操作的方法，但似乎无法使其在这种情况下工作（在轴上带有1值的离散比例尺）。

我已经尝试过转换为数值，并根据此响应使用expand（c（0,0）。当应用于x轴而不是y轴时，它可以工作（可能是因为y轴上只有一个中断？）

library(tidyverse)

df <- tibble(Site = rep("A", 4), 
             Basin = rep("B1", 4), 
             Variable = c("V1", "V2", "V3", "V4"), 
             cls = c("up", "down", "ns", "up"))

#basic plot (output above)
p <- ggplot(df , aes(x=Variable, y=Site)) +
  geom_point(size=3, aes(color=cls, shape=cls, fill=cls)) + 
  facet_grid(Basin~., scales="free", space="free")
p

#attempting to convert discrete scale to continuous and apply limits to axis
p2 <- ggplot(df , aes(x=Variable, y=c(as.numeric(factor(df$Site)))) +
  geom_point(size=3, aes(color=cls, shape=cls, fill=cls)) + 
  scale_y_continuous(limits=c(0.95,1.05),breaks=1,labels=levels(factor(df$Site)), expand=c(0,0))+
  facet_grid(Basin ~ ., scales="free", space="free")

#I have also tried using 
  scale_y_discrete(expand=expand_scale(mult = c(0.01, .01)))



#when same method is applied to the axis it seems to work - is this because there is more than 1 break/variable
 p3 <- ggplot(df , aes(x=as.numeric(df$Variable), y=as.numeric(factor(df$Site)))) +
  geom_point(size=3, aes(color=cls, shape=cls, fill=cls)) + 
  scale_x_continuous(limits=c(0.95,4.05),breaks=seq(1:length(unique(df$Variable))),labels=levels(factor(df$Variable)),
                      expand=c(0,0))+
  facet_grid(Basin~., scales="free", space="free")

yake84

您可以expand_scale()用来调整轴的极限。该mult参数会将当前比例的最小值和最大值乘以您给出的百分比。mult = c(0.2, 1)意味着将到底部的距离减少到当前距离的20％，并将到顶部的距离保持在原始距离。

ggplot(df, aes(x = Variable, y = Site)) +
  geom_point(aes(color = cls, shape = cls, fill = cls), size = 3) +
  facet_grid(Basin ~ ., scales = "free", space = "free") +
  scale_y_discrete(expand = expand_scale(mult = c(0.2, 1)))