I am creating an R Shiny dashboard that includes a datatable displayed using the DT package. I have column filters displayed at the top of each column, but I want to slightly change the behavior of the filters so that a user can search for one item in a list and find all rows containing that item. For example, I have a column containing a list of food items in each row: “apples, bananas, lettuce”, “pears, apples, pineapple”, “apples, lettuce”. I want the user to be able to select any of the individual items to filter for rows that contain that item in their list. For example, if a user selected “lettuce,” the table would show the first and third examples I just listed.

This is an example of the functionality I’m looking for in an R Shiny reprex:

library(shiny)
library(DT)

# Sample data frame
data <- data.frame(
  id = 1:5,
  produce = c("apples, pears", "bananas, pears, lettuce", "apples, bananas, pineapple", "apples", "pineapple, lettuce")
)

# Define UI
ui <- fluidPage(
  titlePanel("Produce Filter"),
  sidebarLayout(
    sidebarPanel(
      selectInput("produce_filter", "Select Produce:", 
                  choices = unique(unlist(strsplit(data$produce, ", "))),
                  selected = NULL, 
                  multiple = TRUE)
    ),
    mainPanel(
      DTOutput("filtered_table")
    )
  )
)

# Define server logic
server <- function(input, output) {
  
  filtered_data <- reactive({
    # Get selected produce items
    selected_produce <- input$produce_filter
    
    # Check if selected_produce is NULL or empty
    if (is.null(selected_produce) || length(selected_produce) == 0) {
      # If no produce is selected, show all rows
      return(data)
    }
    
    # Filter rows where 'produce' column contains any of the selected items
    filtered <- data[sapply(data$produce, function(row) {
      any(sapply(selected_produce, function(item) grepl(item, row)))
    }), ]
    
    # Handle the case where the filtered data is empty
    if (nrow(filtered) == 0) {
      filtered <- data.frame(id = integer(0), produce = character(0))  # Return an empty data frame with the same columns
    }
    
    filtered
  })
  
  output$filtered_table <- renderDT({
    datatable(filtered_data())
  })
}

# Run the application 
shinyApp(ui = ui, server = server)

This table does exactly what I want, but I’m wondering if it’s possible for the DT table column filters to do this, rather than having an external filter that does it. I will need to apply this to several columns, so it will not be ideal to have five separate filters next to the table.