I am trying to set up a table, where in every row there are variable names, and the user should be able to define a formula based on them.

Below is my attempt with orderInput.

Issues:

A) How to use a reset button? When I try to define the formula for the next row, I cannot delete the old one.

B) when I use " as_source = T" in the foo orderInput, the orderInputupdate does not work any more.

Any other solutions, apart from orderInput, are more than welcome.

Many great thanks!

```
library(DT)
library(shiny)
library(shinyjqui)
library(dplyr)
some_vars = head(mtcars, 8) %>% select(am, gear, carb) %>% mutate(
am = paste0("v", am),
gear = paste0("x", gear),
carb = paste0("y", carb),
formula = NA
)
ui <- basicPage(
h2("build a formula"),
orderInput(
"ops",
"Operators",
c("~", "+", "*"),
as_source = T,
connect = "formula",
item_class = "default"
),
orderInput(
"foo",
"foo",
items = month.abb[1:3],
connect = "formula",
item_class = 'info'
),
orderInput(
"formula",
"Formula",
items = NULL,
as_source = F,
connect = NULL,
placeholder = "(build your formula)"
),
verbatimTextOutput("myFormula"),
actionButton("forml", "define the formula for the selected row"),
actionButton("get_forml", "Get the formula for the selected row"),
h2("The variables table"),
DT::dataTableOutput("mytable")
)
server <- function(input, output, session) {
df=reactiveVal(some_vars)
output$mytable = DT::renderDataTable({
DT::datatable(df(),
selection = "single")
})
observeEvent(input$forml, {
updateOrderInput(session,
"foo",
items =
unname(as.character(some_vars[input$mytable_rows_selected, 1:3])),
item_class = "success")
})
output$myFormula <- renderPrint({
paste0(input$formula, collapse = " ")
})
observeEvent(input$get_forml, {
temp=isolate(df())
temp[input$mytable_rows_selected,"formula"]= paste0(input$formula, collapse = " ")
df(temp)
})
}
shinyApp(ui, server)
```