R: error in ggplot:argument "env" is missing, with no default - r

Question

Shiny newbie here.
I am trying to write a R shiny script, and one of things I want to do is generate various plots.
I have a written this code for plotting by taking input from user but getting error of
Error in exists(name, envir = env, mode = mode) :
argument "env" is missing, with no default
Need Help to solve this
I am uploading my server and ui code.
Server.r
shinyServer(function(input,output){
data<-reactive({
file1<-input$file
if(is.null(file1)){return()}
read.table(file=file1$datapath,sep = input$sep,header = input$header,stringsAsFactors = input$stringAsFactors)
})
output$variable <- renderUI({
obj<-data()
if (is.null(obj))
return(NULL)
var.opts<-namel(colnames(obj))
selectInput("variable","Variable:", var.opts)
})
# y variable
output$group <- renderUI({
obj<-data()
if (is.null(obj))
return(NULL)
var.opts<-namel(colnames(obj))
selectInput("group","Groups:", var.opts)
})
#caption
output$caption<-renderText({
switch(input$plot.type,
"boxplot" = "Boxplot",
"histogram" = "Histogram",
"density" = "Density plot",
"bar" = "Bar graph")
})
#plot
output$plot <- renderUI({
plotOutput("p")
})
#plotting function using ggplot2
output$p <- renderPlot({
obj<-data()
plot.type<-switch(input$plot.type,
"boxplot" = geom_boxplot(),
"histogram" = geom_histogram(alpha=0.5,position="identity"),
"density" = geom_density(alpha=.75),
"bar" = geom_bar(position="dodge")
)
require(ggplot2)
#plotting theme
.theme<- theme(
axis.line = element_line(colour = 'gray', size = .75),
panel.background = element_blank(),
plot.background = element_blank()
)
if(input$plot.type=="boxplot") { #control for 1D or 2D graphs
p<-ggplot(data=obj,
aes(
x = obj$group,
y = obj$variable,
fill = as.factor(obj$group)
)
) + plot.type
if(input$show.points==TRUE)
{
p<-p+ geom_point(color='black',alpha=0.5, position = 'jitter')
}
} else {
p<-ggplot(data=obj,
aes(
x = obj$variable,
fill = as.factor(obj$group),
group = as.factor(obj$group)
#color = as.factor(plot.obj$group)
)
) + plot.type
}
p<-p+labs(
fill = input$group,
x = "",
y = input$variable
) +
.theme
print(p)
})
})
ui.R
shinyUI(fluidPage(
#Heading panel
titlePanel(title="Machine Learning and Statistics",),
#input data set
sidebarLayout(position = "right",
sidebarPanel(fileInput('file', 'Choose a File', multiple = T, accept=c('text/csv',
'text/comma-separated-values,text/plain',
'.csv')),
#default size for dataset
helpText("Default max. size is 7mb"),
#input number of observations
numericInput("obs", "Number of observations to view:", 10),
tags$hr(),
checkboxInput(inputId = 'header',label = 'Header',value = TRUE),
checkboxInput(inputId = "stringAsFactors","stringAsFactors",TRUE),
br(),
radioButtons(inputId = 'sep',label = 'Seprator',choices=c(comma=',',Semicolon=';',Tab='\t',Space=' '),selected = ','),
sliderInput("train_percent",
"Training Percentage:",
min = 10, max = 90,
value = 20, step = 10),
uiOutput("variable"), # depends on dataset ( set by output$variable in server.R)
uiOutput("group"), # depends on dataset ( set by output$group in server.R)
selectInput("plot.type","Plot Type:",
list(boxplot = "boxplot", histogram = "histogram", density = "density", bar = "bar")
),
checkboxInput("show.points", "show points", TRUE)
),
mainPanel(
("output"),
h3(textOutput("caption")),
uiOutput("plot")
)
)))
Help?Thanks.

Answer 1

My solution to this error message when using ggplot in Shiny is:
ggplot(data = obj, aes(...), environment = environment())
Would appreciate if someone could explain the reason behind the extra need for this in a Shiny app.