R - 在R函数内创建数据帧并在该数据帧上使用ggplot

I think I am having an issue regarding variable scope but can't figure out how to work around it. Essentially I create a data frame in an R function and then use ggplot to call variables out of that data frame. I keep getting an error stating that the object dataframe was not found.I think I am having an issue regarding variable