任务一：

> library(ggplot2)

> plot1<- ggplot(mtcars,aes(factor(cyl)))+geom_bar(aes(fill=factor(gear)),width = 0.6)+labs(title="Here is title",subtitle="Here is subtitle",caption="Here is caption",x="cyl")+scale_fill_discrete(name="gear")

plot1

> mytheme<- theme_classic()+theme(panel.grid.major = element_blank(),panel.grid.minor = element_blank(),legend.position = "none",plot.caption = element_text(face = "bold.italic"))

> plot1+mytheme

任务二：

> library(ggplot2)

> library(latex2exp)

> myvolcano <- read.csv("/Users/LUCY/Desktop/科研狗R语言第二期/2-7/Volcanoplot/nature23643-s4.csv")

> myvolcano$significant <- ifelse((abs(log2(myvolcano$FC))>1 & abs(log2(myvolcano$q_value))>5),"YES","NO")

> myvolcano$mylabels <- ifelse((abs(log2(myvolcano$FC))>1 & abs(log2(myvolcano$q_value))>5),as.character(myvolcano$Gene.ID),NA)

> mysig <- subset(myvolcano,significant == "YES")

> ydrop = -0.6

> textdrop = 0.3

> myplot <- ggplot(myvolcano,aes(x = log2(FC) , y = -log2(q_value),size = significant)) +geom_point(col = "grey70",alpha = 1) + xlim(-2.5,2.7) +ylim(-0.8,15) +scale_size_manual(values = c(2,0)) +geom_point(data = mysig,aes(x = log2(FC),y = -log2(q_value),col = mylabels),size = 4,position = position_jitter(height = 0.1,width = 0)) +geom_text(aes(label = mylabels),size =3,hjust = 0,vjust =-1,col = "black",fontface = "italic") +annotate("segment", x = 1 , xend = 2.5, y = ydrop,yend  =ydrop ,color = "black",size = 1,arrow = arrow(angle = 18,ends = "last",type ="closed")) +  annotate("segment", x = -1 , xend = -2.5, y = ydrop,yend  = ydrop ,color = "black",size = 1,arrow = arrow(angle = 18,ends = "last",type ="closed")) +annotate("text",x = 1.7,y = textdrop,label = "Upregulated",size =4.5) +annotate("text",x = -1.7,y = textdrop,label = "Downregulated",size= 4.5)  +labs(title = "CMTM6 sgRNA2 vs Control",caption = "create by R2-14") +labs(x = expression(log[2])) +labs(x = expression(paste(log[2],"(fold change)")), y = expression(paste(-log[2],"(Q value)"))) 

> myplot

> myplot+mytheme