如何在ggplot2条形图中添加水平闪避标签？

Question

我想将标签添加到一个相当简单的条形图（即，geom_bar）。 position_dodge()在geom_text()内纠正标签的垂直间距，但不纠正水平间距。我怎样才能让ggplot2将我的标签正确地散布在酒吧上方？

library(tidyr) 
library(grid) 
library(ggplot2) 

data = read.table('temp.dat', header=T) 

data <- gather(data, SOA, RT, X0:X1000) 

data$ResponseCondition = as.factor(data$ResponseCondition) 
levels(data$SOA) = c(0,250,500,1000) 
data$SOA = as.numeric(as.character(data$SOA)) 

p = ggplot(data, aes(y=RT, x=SOA, fill=ResponseCondition, ymax=RT*1.05)) 
p = p + geom_bar(stat='identity', position=position_dodge()) 
p = p + geom_text(aes(label=RT), position=position_dodge()) 

p = p + scale_x_continuous(breaks=c(0,250,500,1000)) 

p = p + ylab('Response Time (ms)') 
p = p + xlab('Precue Interval (ms)') 
p = p + theme_bw() 
p = p + scale_fill_grey(start = 0.1, end = .9, name='Response condition') 

p = p + theme(
    axis.title.x = element_text(vjust=-0.30, size=10), 
    axis.title.y = element_text(vjust=1.50, size=10), 
    text = element_text(size=10), 
    legend.justification=c(1,1), legend.position=c(1,1), 
    plot.margin = unit(rep(.5, 4), 'cm')) 

ggsave('temp.png', width=10, height=7.5) 

这里是条形图：

这里是temp.dat来完成一个完整的工作示例所需要的内容：

ResponseCondition 0 250 500 1000 
       28 1254 1056 901 864 
       46 1306 1063 889 772 
       64 1171 939 786 682 
       82 1205 948 821 731 

Answer 1

我认为，最主要的原因为什么它们没有得到恰当的分散是因为SOA不是一个因素变量，你应该保持它的一个因素。此外，如果你跳过scale_x_continuous，你的代码应该可以工作。这就是我通过微小的改变做到的。您可以按照自己的喜好调整垂直距离（vjust）和颜色：

library(tidyr) 
library(grid) 
library(ggplot2) 

data = read.table('temp.dat', header=T) 
data <- gather(data, SOA, RT, X0:X1000) 
data$ResponseCondition = as.factor(data$ResponseCondition) 
levels(data$SOA) = c(0,250,500,1000) 
# data$SOA = as.numeric(as.character(data$SOA)) 

p = ggplot(data, aes(y=RT, x=SOA, fill=ResponseCondition, ymax=RT*1.05)) 
p = p + geom_bar(stat='identity', position=position_dodge()) 
p = p + geom_text(aes(label=RT), colour="purple", vjust=1.5, position=position_dodge(0.9), size=4) 

# p = p + scale_x_continuous(breaks=c(0,250,500,1000)) 

p = p + ylab('Response Time (ms)') 
p = p + xlab('Precue Interval (ms)') 
p = p + theme_bw() 
p = p + scale_fill_grey(start = 0.1, end = .9, name='Response condition') 

p = p + theme(
    axis.title.x = element_text(vjust=-0.30, size=10), 
    axis.title.y = element_text(vjust=1.50, size=10), 
    text = element_text(size=10), 
    legend.justification=c(1,1), legend.position=c(1,1), 
    plot.margin = unit(rep(.5, 4), 'cm')) 

ggsave('temp.png', width=10, height=7.5)