shiny Error in match.arg(position) : 'arg' must be NULL or a character vector

Question

I went into an error when running my shiny app. The error seems in ui.R but I have checked so many times and still can\'t figure it out. Does anyone have ideas? Here\'s my c

Answer 1

It's in your call to sidebarLayout (it's in your error message trace). If you look at ?sidebarLayout, it takes 4 arguments

function (sidebarPanel, mainPanel, position = c("left", "right"), 
    fluid = TRUE) 
{
    position <- match.arg(position)
    ...

The third argument is a string "left" or "right" being the position. Your third argument seems to be a mainPanel and you are passing in two sidebarPanels. That's why you are getting that argument.