ggplot(kegg_class,aes(x = Description,y = Count)) + geom_bar(aes(fill = source),stat = "identity",width = 0.5,position = "dodge") + scale_fill_manual(values = c(up = "#ca0020",down = "#2b83ba")) + theme_classic()+
scale_y_continuous(expand = c(0,0))+ #去掉與Y軸間隙
labs(x = "" , y = "count",title = "")+ #修改x,y軸的標題
theme(axis.title.x = element_text(size = 14,face = "bold"),axis.title.y = element_text(size = 14,face = "bold"))+ # x軸標題，y軸標題字體的大小
theme(axis.text.x = element_text(size = 9,face = "bold"),axis.text.y = element_text(size = 9,face = "bold"))+ #修改x，y軸刻度線上的大小
theme(axis.ticks.y = element_blank())+ # 只刪掉y軸的刻度線,theme(axis.ticks = element_blank()) 刪掉所有的刻度線
theme(legend.position = "right") + # legend的位置，可旋轉right,left,top,bottom,none
theme(legend.position = c(0.7,0.3))+#legend.position也可以用兩個元素構成的數值向量來控制，主要是設置圖例在圖片中間所在具體位置
coord_flip()