R 剪切作为参数传递给用户定义函数的datatable变量

我在“helpers.R”中有一个名为“percent_map”的用户定义函数，它接受以下参数：

percent_map <- function(DT,var,statelist, pal,legend.title)

如何解决这个问题，使最终结果相同？这是str（visabystate）

但是，如果在percent_map函数中的cut内使用DT$var，则该函数不起作用。它给出了同样的错误

编辑

在cut语句中添加了=FALSE，如下所示

DT[,percents:=as.integer(cut(DT[,var,with=FALSE], 5, include.lowest = TRUE))]

它提供了以下附加信息：

    percent_map <- function(DT,var,statelist, pal, legend.title) {

      # generate vector of fill colors for map
      shades <- RColorBrewer::brewer.pal(5, pal)

      # constrain gradient to percents that occur between variable range
      ##********Error in the below statement*************
      DT[,percents:=as.integer(cut(DT[,var], 5, include.lowest = TRUE))]



      names <- DT[match(map("state", plot=FALSE)$names,as.character(tolower(DT[,statelist]))),statelist]
      colorsmatched<-DT[match(names,as.character(DT[,statelist])),percents]
      fills <- shades[colorsmatched]  

#map plotting function here 
    }

The following objects are masked from DT (pos = 3):

    casesbystate, employer_state, fulltimebystate, workersbystate

The following objects are masked from DT (pos = 4):

    casesbystate, employer_state, fulltimebystate, workersbystate

The following objects are masked from DT (pos = 5):

    casesbystate, employer_state, fulltimebystate, workersbystate

 Show Traceback

 Rerun with Debug
 Error in cut.default(DT[, var, with = FALSE], 5, include.lowest = TRUE) : 
  'x' must be numeric 

---

提前谢谢

我认为问题来自

var='casesbystate'

。它应该是

var=casesbystate

（不带引号）。查看

visabytate[，'casesbystate']

和

visabytate[，casesbystate]

之间的差异。或者，如果要在对

data.table

进行子集设置时传递字符串，可以使用

with=FALSE

参数。是的，我也这样认为。但是，我需要将变量名作为参数传递，而将其作为字符串传递似乎是唯一的方法。不幸的是，with=FALSE不起作用。我已经更新了问题以显示错误，您应该开始新的会话。但是，如果需要单个列，标准的

DT[[var]]

应该可以使用。只需使用

DT[[var]]

而不是

DT[，var]

。数据表FAQ:@user227710-这是一个整数。我试图错误地提取列。

visabystate[,percents:=as.integer(cut(visabystate[,casesbystate], 5, include.lowest = TRUE))]

DT[,percents:=as.integer(cut(DT[,var,with=FALSE], 5, include.lowest = TRUE))]

The following objects are masked from DT (pos = 3):

    casesbystate, employer_state, fulltimebystate, workersbystate

The following objects are masked from DT (pos = 4):

    casesbystate, employer_state, fulltimebystate, workersbystate

The following objects are masked from DT (pos = 5):

    casesbystate, employer_state, fulltimebystate, workersbystate

 Show Traceback

 Rerun with Debug
 Error in cut.default(DT[, var, with = FALSE], 5, include.lowest = TRUE) : 
  'x' must be numeric