ggplot2拼图共享图例（指定图例）相关设定—科研工具箱

涉及拼图时，有时几个图图例并不完全一样，这时候如何处理，直接上代码（以pancancer生存分析数据为例），此处用到lomon和gridExtra包

library(ggplot2)
setwd(\"G:/test\")
unicox1 <- read.csv(\"OS_pancan_unicox.csv\")
unicox1 <- unicox1[order(unicox1$HR,decreasing = F),]
unicox1$cancer <- factor(unicox1$cancer, levels = unicox1$cancer)
unicox2 <- read.csv(\"PFI_pancan_unicox.csv\")
unicox2$cancer <- factor(unicox1$cancer, levels = unicox1$cancer)
unicox3 <- read.csv(\"DSS_pancan_unicox.csv\")
unicox3$cancer <- factor(unicox1$cancer, levels = unicox1$cancer)
unicox4 <- read.csv(\"DFI_pancan_unicox.csv\")
unicox4$cancer <- factor(unicox1$cancer, levels = unicox1$cancer)

p1 <- ggplot(unicox1, aes(HR,  cancer,  col=Type,shape=Type))+
  geom_point(aes(size=-log10(p.value)))+
  geom_errorbarh(aes(xmax =upper_95, xmin = lower_95), height = 0.4)+
  scale_x_continuous(limits= c(-2, 2), breaks= seq(-1, 1, 1))+
  geom_vline(aes(xintercept = 0))+
  xlab(\'HR(95%CI)\') + ylab(\' \')+
  theme_bw(base_size = 12)+
  ggtitle(\"OS\")+
  theme(plot.title = element_text(hjust = 0.5, size=10))+
  scale_color_manual(values = c(\"gray\", \"blue\", \"red\"))+theme(legend.position=\'none\')


p2 <- ggplot(unicox2, aes(HR,  cancer,  col=Type,shape=Type))+
  geom_point(aes(size=-log10(p.value)))+
  geom_errorbarh(aes(xmax =upper_95, xmin = lower_95), height = 0.4)+
  scale_x_continuous(limits= c(-2, 2), breaks= seq(-1, 1, 1))+
  geom_vline(aes(xintercept = 0))+
  xlab(\'HR(95%CI)\') + ylab(\' \')+
  theme_bw(base_size = 12)+
  ggtitle(\"PFI\")+
  theme(plot.title = element_text(hjust = 0.5, size=10))+guides(shape=FALSE) +
  scale_color_manual(values = c( \"blue\", \"red\",\"gray\"),
                     breaks = c(\"Protective\",\"Risky\",\"NS\"),
                     labels = c(\"Protective\",\"Risky\",\"NS\"))+theme(legend.position=\'none\')

p3 <- ggplot(unicox3, aes(HR,  cancer,  col=Type,shape=Type))+
  geom_point(aes(size=-log10(p.value)))+
  geom_errorbarh(aes(xmax =upper_95, xmin = lower_95), height = 0.4)+
  scale_x_continuous(limits= c(-2, 2), breaks= seq(-1, 1, 1))+
  geom_vline(aes(xintercept = 0))+
  xlab(\'HR(95%CI)\') + ylab(\' \')+
  theme_bw(base_size = 12)+
  ggtitle(\"DSS\")+
  theme(plot.title = element_text(hjust = 0.5, size=10))+
  scale_color_manual(values = c(\"gray\", \"blue\", \"red\"))+theme(legend.position=\'none\')

p4 <- ggplot(unicox4, aes(HR,  cancer,  col=Type,shape=Type))+
  geom_point(aes(size=-log10(p.value)))+
  geom_errorbarh(aes(xmax =upper_95, xmin = lower_95), height = 0.4)+
  scale_x_continuous(limits= c(-2, 2), breaks= seq(-1, 1, 1))+
  geom_vline(aes(xintercept = 0))+
  xlab(\'HR(95%CI)\') + ylab(\' \')+
  theme_bw(base_size = 12)+
  ggtitle(\"DSS\")+
  theme(plot.title = element_text(hjust = 0.5, size=10))+
  scale_color_manual(values = c(\"gray\", \"blue\", \"red\"))+theme(legend.position=\'none\')

library(gridExtra)
library(lemon)
legend <- g_legend(p2)
grid.arrange(p1, p2,p3,p4,
             ncol = 4, nrow = 1,right=legend)