无法将用户定义函数中的参数传递给ggplot

Question

我想创建一个用户定义的函数，它包装了我找到的一些流行的ggplot代码。我收到以下错误：

"Error in `[.data.frame`(DS, , xvar) : object 'xcol' not found" 

下面是一个小的伪数据集来说明这个问题。

n=25
dataTest <- data.frame(xcol=sample(1:3, n, replace=TRUE), ycol = rnorm(n, 5, 2), Cat=letters[1:5])

用户定义的代码如下：

  TRIPLOT <- function (DS,xvar,yvar,zvar) {
 #localenv<-environment()
  gg <- data.frame(x=DS[,xvar],y=DS[,yvar],fill=DS[,zvar])
  empty<-ggplot()+geom_point(aes(1,1),colour="white") + theme( 
    plot.background = element_blank(),
    panel.background = element_blank(),
    panel.grid.minor = element_blank(),
    panel.border = element_blank(),
    panel.background = element_blank(),
    axis.title.x = element_blank(),
    axis.title.y = element_blank(),
    axis.text.x = element_blank(),
    axis.text.y = element_blank(),
    axis.ticks = element_blank())
  scatter <-ggplot(gg, aes_string(x=xvar,y=yvar), environment=environment())+
    geom_point(aes_string(color=zvar))+
    scale_color_manual(values=c("orange","purple"))+
    theme(legend.position=c(1,1), legend.justification=c(1,1))
  plot_top <- ggplot(gg,aes_string(x=xvar, fill=zvar), environment=environment())+geom_density(alpha=.5)+scale_fill_manual(values=c("orange","purple"))+theme(legend.position="none")
  plot_right <- ggplot(gg, aes_string(yvar, fill=zvar),environment=environment())+geom_density(alpha=.5)+coord_flip()+ scale_fill_manual(values=c("orange","purple"))+
    theme(legend.position="none", axis.title.x=element_blank())
  PLT <- grid.arrange(plot_top,empty,scatter,plot_right, ncol=2,nrow=2,widths=c(4,1), heights=c(1,4))
  print(PLT)
}

我尝试运行的函数如下：

TRIPLOT(dataTest,"xcol","ycol","Cat")

我按照post的建议添加了环境参数和data.frame()参数。我还用引号将参数传递给函数。谢谢你的帮助。

Answer 1

将变量名作为字符串传递给函数，在gg数据框中重命名变量；然后使用aes代替aes_string；并在对ggplot的调用中使用gg数据框及其变量名。

或者将变量名作为字符串传递给函数；然后使用aes_string (并跳过gg数据框)。

此外，scale_fill_manual中的颜色数量也存在问题。我已经把这些行注释掉了。

library(gridExtra)
library(ggplot2)

n=25
dataTest = data.frame(
   xcol=sample(1:3, n, replace=TRUE), 
   ycol = rnorm(n, 5, 2), 
   Cat=letters[1:5])

以下任一项：

 TRIPLOT <- function (DS,xvar,yvar,zvar) {
 #localenv<-environment()
  gg <- data.frame(x = DS[,xvar], y = DS[, yvar],fill = DS[,zvar])
  empty<-ggplot()+geom_point(aes(1,1),colour="white") + theme( 
    plot.background = element_blank(),
    panel.background = element_blank(),
    panel.grid.minor = element_blank(),
    panel.border = element_blank(),
    panel.background = element_blank(),
    axis.title.x = element_blank(),
    axis.title.y = element_blank(),
    axis.text.x = element_blank(),
    axis.text.y = element_blank(),
    axis.ticks = element_blank())

  scatter <-ggplot(gg, aes(x = x,y = y))+
    geom_point(aes(color = fill))+
    #scale_color_manual(values=c("orange","purple"))+
    theme(legend.position=c(1,1), legend.justification=c(1,1))

  plot_top <-ggplot(gg,aes(x = x, fill = fill))+
   geom_density(alpha=.5)+
   #scale_fill_manual(values=c("orange","purple"))+
    theme(legend.position="none")

  plot_right <-ggplot(gg, aes(x = y, fill = fill))+
       geom_density(alpha=.5)+coord_flip()+ 
       #scale_fill_manual(values=c("orange","purple"))+
    theme(legend.position="none", axis.title.x=element_blank())

  PLT<-grid.arrange(plot_top,empty,scatter,plot_right, ncol=2,nrow=2,widths=c(4,1), heights=c(1,4))
  print(PLT)
}

TRIPLOT(dataTest,"xcol","ycol","Cat")

或者：

 TRIPLOT <- function (DS,xvar,yvar,zvar) {
 #localenv<-environment()
  #gg <- data.frame(x = DS[,xvar], y = DS[, yvar],fill = DS[,zvar])
  empty<-ggplot()+geom_point(aes(1,1),colour="white") + theme( 
    plot.background = element_blank(),
    panel.background = element_blank(),
    panel.grid.minor = element_blank(),
    panel.border = element_blank(),
    panel.background = element_blank(),
    axis.title.x = element_blank(),
    axis.title.y = element_blank(),
    axis.text.x = element_blank(),
    axis.text.y = element_blank(),
    axis.ticks = element_blank())

  scatter <-ggplot(DS, aes_string(x = xvar,y = yvar))+
    geom_point(aes_string(color = zvar))+
    #scale_color_manual(values=c("orange","purple"))+
    theme(legend.position=c(1,1), legend.justification=c(1,1))

  plot_top <-ggplot(DS,aes_string(x = xvar, fill = zvar))+
   geom_density(alpha=.5)+
   #scale_fill_manual(values=c("orange","purple"))+
    theme(legend.position="none")

  plot_right <-ggplot(DS, aes_string(x = yvar, fill = zvar))+
       geom_density(alpha=.5)+coord_flip()+ 
       #scale_fill_manual(values=c("orange","purple"))+
    theme(legend.position="none", axis.title.x=element_blank())

  PLT<-grid.arrange(plot_top,empty,scatter,plot_right, ncol=2,nrow=2,widths=c(4,1), heights=c(1,4))
  print(PLT)
}

TRIPLOT(dataTest,"xcol","ycol","Cat")

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