R - 是否可以填写保存为对象的函数参数？

Question

map_basic <- leaflet::leaflet() %>%
             leaflet::addMarkers(
                data = flow_stations,
                group = "Stream Flow Stations",
                options = leaflet::leafletOptions(pane="marker"),                    
                label = paste0(flow_stations$`Data Source`, ": ", flow_stations$Station, " (", flow_stations$`Station ID`,")"),
                labelOptions = labelOptions(textsize = "15px"),
                popup = ~paste0("<b>", 
                                flow_stations$`Data Source`," Station Name: ",
                                flow_stations$Station,"<br>",
                                "Station ID: ", flow_stations$`Station ID`,
                                sapply(flow_stations$Station, 
                                       popupTable.flow, USE.NAMES = FALSE)),
                popupOptions = leaflet::popupOptions(maxWidth = 650, maxHeight = 300))

在上面的代码中，我可以将参数保存在一个对象中并在leaflet::addMarkers() 的函数中使用该对象吗？ 例如，

flowStations <- paste0(
                   'data = flow_stations,',
                   'group = "Stream Flow Stations",',
                   'options = leaflet::leafletOptions(pane="marker"),',                       
                   'label = paste0(flow_stations$`Data Source`, ": ", flow_stations$Station, " (", flow_stations$`Station ID`,")"),',
                   'labelOptions = labelOptions(textsize = "15px"),',
                   'popup = ~paste0("<b>", ',
                                   'flow_stations$`Data Source`," Station Name: ",',
                                   'flow_stations$Station,"<br>",',
                                   '"Station ID: ", flow_stations$`Station ID`,',
                                   'sapply(flow_stations$Station, ',
                                          'popupTable.flow, USE.NAMES = FALSE)),',
                   'popupOptions = leaflet::popupOptions(maxWidth = 650, maxHeight = 300)')

然后，将代码简化为如下所示的内容以进行测试。

map_basic <- leaflet::leaflet() %>%
             leaflet::addMarkers(flowStations)

测试代码的错误信息是

在derivePoints(data, lng, lat, missing(lng), missing(lat), "addMarkers") 中出错：未找到点数据； 请为 addMarkers 提供数据和/或 lng/lat 参数

任何人有想法让它工作，请分享。 谢谢！

** 更新 *********************************************** *****************

感谢您的所有建议。 我在下面添加了一个非常简单的可重现脚本。

Station <- c("Station 1","Station 2")
Lat <- c("45.11373","45.07123")
Long <- c("-121.8151","-121.9406")
flow_stations <- data.frame(Station, Lat, Long) %>% 
   sf::st_as_sf(coords = c("Long","Lat"), crs = sf::st_crs("+init=EPSG:4326"))

map_basic <- leaflet::leaflet() %>%
   leaflet::addMarkers(data = flow_stations,
                       label = flow_stations$Station)

我试图将参数添加到列表中。

flowStations <- list("data = flow_stations",
                     "label = flow_stations$Station")

然后根据@r2evans的建议在下面尝试。

map_basic <- leaflet::leaflet() %>%
   do.call(leaflet::addMarkers,flowStations)

我得到了错误：

do.call(., Leaflet::addMarkers, flowStations) 中的错误：第二个参数必须是一个列表

我可能没有正确使用 do.call。 更多建议？

Answer 1

如果将参数保存为列表（而不是字符串），则可以使用 do.call()。 你的代码是不可复制的，但这里有一个例子展示了这个想法：

args = list(
  x = 1:10,
  y = 2:20
)

do.call(what = t.test, args = args)

它将使用args的命名参数调用函数t.test 。

Answer 2

您可以编写一个辅助函数，而不是将 cpde 存储为字符串。 例如

myAddMarkers <- function(plot, data) {
  leaflet::addMarkers(
    plot, data = data,
    group = "Stream Flow Stations",
    options = leaflet::leafletOptions(pane = "marker"),
    label = paste0(data$`Data Source`,": ", data$Station," (", data$`Station ID`,")"),
    labelOptions = labelOptions(textsize = "15px"),
    popup = ~ paste0(
      "<b>", data$`Data Source`,
      " Station Name: ", data$Station, "<br>",
      "Station ID: ", data$`Station ID`,
      sapply(data$Station, popupTable.flow, USE.NAMES = FALSE)
    ),
    popupOptions = leaflet::popupOptions(maxWidth = 650, maxHeight = 300)
  )
}

然后对于要使用这些设置的所有图，您可以使用

map_basic <- leaflet::leaflet() %>% myAddMarkers(flow_stations)