编辑代码

drawt<-function(...,lit=c(10,-10),colo=NULL){
  library(ggplot2)
  library(dplyr)
  library(reshape2)
  #n=...length()
  args<-list(...)     ##获取所有参数
  x <- seq(lit[1],lit[2],length=10000)
  Y<-as.data.frame(x)
  cn<-c('x')
  for(a in args){
    
    y<- dt(x,a)
    Y<-cbind(Y,y)
    a <- as.character(a)
    cn<-append(cn,paste('df',a,sep =""))
  }
  colnames(Y) <- cn
  Y2 <- melt(Y,id.var="x",variable.name = 'df',value.name = 'y')
  ggplot(data = Y2, aes(x = x, y = y,col=df,linetype=df)) + 
    geom_line(size = 1) + 
    labs(x='x',y='概率密度',title='t分布与正态分布',color='类型',linetype='类型')+               ##坐标轴文字与标题
    theme_light()+                                                                           ##主题
    theme(plot.title = element_text(size=20,hjust=0.5,vjust=0.5))
}
drawt(2,30)