本节介绍一下用ggplot2绘制带箭头的条形图，很简单的绘图案例，但是用到了很多的画图函数，希望对大家学习ggplot2绘图有所帮助
加载R包
library(tidyverse)
library(ggsci)
创建数据集
p <- tribble(
~start, ~end,~group,
-15,-10,"A",
-10,-5,"B",
-5,0,"C",
0,5,"D",
5,10,"E",
10,15,"G")
数据可视化
p1 <- ggplot(p) +
geom_segment(aes(x=15,xend=17,y=0,yend=0),
arrow = arrow(length = unit(1.5,"cm"),
type="closed"),
arrow.fill="#78B7C5",colour="white")+
geom_segment(aes(x=-15,xend=-17,y=0,yend=0),
arrow = arrow(length = unit(1.5,"cm"),
type="closed"),
arrow.fill="#78B7C5",colour="white")+
geom_rect(aes(xmin=start, xmax=end,ymin=-0.3,ymax=0.3,
fill=group),colour="white")+
geom_text(data=p,aes(x=start+2.5,y=0,label=group),
fill="white",size=4,colour="white")+
scale_fill_nejm()+ ylim(c(-1,1))+
theme(legend.position="non",
legend.key.size=unit(0.5,'cm'),
legend.key.height=unit(0.5,'cm'),
legend.key.width=unit(0.5,'cm'),
legend.title=element_blank(),
axis.text.y=element_blank(),
axis.text.x = element_blank(),
axis.ticks.x=element_blank(),
axis.ticks.y=element_blank(),
panel.background = element_blank())+
labs(x=NULL,y=NULL)+
guides(fill = guide_legend(ncol=6))+
annotate("text",x = 10, y =-0.4, label = "10",
colour = "black",size = 4)+
annotate("text",x = 15, y =-0.4, label = "15",
colour = "black",size = 4)+
annotate("text",x = 5, y =-0.4, label = "5",
colour = "black",size = 4)+
annotate("text",x = 0, y =-0.4, label = "0",
colour = "black",size = 4)+
annotate("text",x = -5, y =-0.4, label = "-5",
colour = "black",size = 4)+
annotate("text",x = -10, y =-0.4, label = "-10",
colour = "black",size = 4)+
annotate("text",x = -15, y =-0.4, label = "-15",
colour = "black",size = 4)
ggsave(p1,file="gene.pdf",width =9.74,height=2.19,units="in",dpi=300)