r - Creating a generic function generating new objects from selected list of columns in a data frame -

i'm working on simple shinyapp enable end-users interrogate data use of various filters. of filters correspond unique values in data frame columns created using code corresponding example below:

# source sample data data(mtcars) # put menu element mtcars$cyl <- as.character(mtcars$cyl) ui_list_cyl <- unique(mtcars$cyl) 

i' subsequently introducing elements created in manner shiny drop down widget, in code below:

# sample widget elements provides access unique column values selectinput("select", label = h3("select box"),      choices = ui_list_cyl,      selected = 1), 

i'm repeating same procedure number of columns , creating function address requirement appears natural choice. in particular, envisage function to:

1. be applicable set of columns pass onto it
2. create objects corresponding interface elements names ui_list_originalcolumname

my question be: how create function can dynamically applied arbitrary selection of columns in data frame , return objects names incorporating passed column names?

there's several ways write function want. here's example of such function accepts dataset , column name , creates associated select input.

myselectinput <- function(data, col) {   id <- sprintf("select_%s", col)   label <- sprintf("select %s", col)   choices <- sort(unique(data[[col]]))   selectinput(id, label, choices) } 

you can use in shiny app so

runapp(shinyapp(   ui = fluidpage(     lapply(c("cyl", "gear", "carb"), function(x) myselectinput(mtcars, x))   ),   server = function(input, output, session) {   } )) 

this create 3 select inputs cyl, gear, carb variables. hope helps, can take here , apply need