library(shiny)

library(ggplot2)

library(dplyr)

library(broom)

grouping <- c('cyl',"vs","am","gear")

varmap <- list ('Displacement' ='disp',

'Gross horsepower'='hp',

'Rear axle ratio'='drat',

'Weight'='wt',

'1/4 mile time'='qsec',

'Number of carburetors'='carb')

groupmap <- list(

'None'='none',

#'Number of cylinders'='cyl',

'V/S'='vs',

'Transmission'='am')

##'Number of forward gears'='gear')

mainplot <- function(variable,group){

plotmap <- ggplot(data=mtcars,aes_string(x=variable,y="mpg"))

if (group == "none"){

baseplot <- plotmap + geom_point(size=3,color="salmon")

} else {

baseplot <-plotmap + geom_point(aes_string(color=group),size=3) + facet_grid(paste0(".~",group))

}

baseplot + geom_smooth(method="lm")

}

my_group_by <- function(datatb,group){

#Takes a data table and a character string

if(group=='none'){

return(datatb)

}else{

group_by_(datatb,group)

}

}

#make these two variable categorical

mtcars <- mtcars %>% mutate(am=as.factor(am))%>%mutate(vs=as.factor(vs))

shinyServer(

function(input,output){

output$edaplot <- renderPlot({

mainplot(varmap[[input$variable]],groupmap[[input$groupby]])

})

output$modelplot <- renderPlot(

{

baseplot <- mtcars %>%

my_group_by(groupmap[[input$groupby]])%>%

do(tidy(lm(as.formula(paste0("mpg~",varmap[[input$variable]])),data=.),conf.int=T))%>%

ggplot(aes_string('term','estimate'))+

geom_errorbar(aes(ymin=conf.low,ymax=conf.high))

if (groupmap[[input$groupby]]=="none"){

baseplot + geom_point(color="salmon",size=3)

}else{

baseplot + geom_point(aes_string(color=groupmap[[input$groupby]]),size=3)

}

})

output$residplot <- renderPlot(

{

baseplot <- mtcars %>%

my_group_by(groupmap[[input$groupby]])%>%

do(augment(lm(as.formula(paste0("mpg~",varmap[[input$variable]])),data=.)))%>%

ggplot(aes_string(varmap[[input$variable]],'.resid')) +

geom_hline(yintercept=0)

if (input$groupby=='None'){

baseplot + geom_point(color='salmon',size=3)

}else{

baseplot + facet_grid(paste0('.~',groupmap[[input$groupby]])) +

geom_point(aes_string(color=groupmap[[input$groupby]]),size=3)

}

}

)

}

)