我认为这是不可能的formatStyle.这里有一个部分解决方案.它是部分的，因为它不处理0的情况，当没有值为正值时，0必须为红色.我会考虑的

library(shiny)
library(DT)

ui <- fluidPage(
  br(),
  DTOutput("weight_df")
)

server <- function(input, output, session){
  
  df <- data.frame(weight = c(-1, 0, 2))
  
  rdf <- reactiveVal(df)
  
  output$weight_df <- renderDT({
    
    datatable(
      data = df,
      rownames = TRUE,
      caption  = htmltools::tags$caption("Weight table"),
      editable = list(target = "cell"),
      options = list(
        rowCallback = JS(js)
      )
    ) 
  })
  
  table_proxy <- dataTableProxy("weight_df")
  
  observeEvent(input$weight_df_cell_edit, {
    info <- input$weight_df_cell_edit
    dat <- rdf()
    rdf(editData(dat, info, table_proxy, rownames = TRUE))
  })
}

shinyApp(ui, server)

Update

它处理0的特定情况:

library(shiny)
library(DT)

js <- c(
  "function(row, dat, displayNum, index){",
  "  var color = dat[1] >= 0 ? 'green' : 'red';",
  "  $('td:eq(1)', row).css('background-color', color);",
  "}"
)

js <-  c(
  "function(settings) {",
  "  var table = settings.oInstance.api();",
  "  var nrows = table.rows().count();",
  "  var allnegative = true;",
  "  var i = 0;",
  "  while(allnegative && i < nrows) {",
  "    var weight = table.cell(i, 1).data();",
  "    allnegative = allnegative && weight <= 0;",
  "    i++;",
  "  }",
  "  for(var k = 0; k < nrows; k++) {",
  "    var cell = table.cell(k, 1);",
  "    var weight = cell.data();",
  "    var color = allnegative ? 'red' : 'green';",
  "    if(weight > 0) {",
  "      color = 'green';",
  "    } else if(weight < 0) {",
  "      color = 'red';",
  "    }",
  "    cell.node().style.backgroundColor = color;",
  "  }",
  "}")

ui <- fluidPage(
  br(),
  DTOutput("weight_df")
)

server <- function(input, output, session){
  
  df <- data.frame(weight = c(-1, 0, 2))
  
  rdf <- reactiveVal(df)
  
  output$weight_df <- renderDT({
    
    datatable(
      data = df,
      rownames = TRUE,
      caption  = htmltools::tags$caption("Weight table"),
      editable = list(target = "cell"),
      options = list(
        drawCallback = JS(js)
      )
    ) 
  })
  
  table_proxy <- dataTableProxy("weight_df")
  
  observeEvent(input$weight_df_cell_edit, {
    info <- input$weight_df_cell_edit
    dat <- rdf()
    rdf(editData(dat, info, table_proxy, rownames = TRUE))
  })
}

shinyApp(ui, server)