Question

我正在尝试运行以下代码：

df[,{
r10s     <- 1:.N/.N < .1
myrows   <- if(sum(r10s)>0){r10s}else{TRUE}
c(
    .SD[myrows],
    list(first10=mean(day[r10s]))
)
 },.(species,year)]

我之前使用过它并且完全没问题，但现在我收到了错误消息：

[.data.frame中的错误（数据，{：找不到功能“。”

我已经加载，库，卸载并重新安装了包，没有任何作用......

我的数据示例，我确实有更多的列和行，但基本上每行都是对具有相应数据的物种的观察

  df=data.frame(
  year=c(1901,1901,1901,1901,1901,1901,1901,1901,1901,1901,1901,1901,1901),
  temp=c(29,25,21,26,20,20,26,25,24,23,23,24,26),
  habitat=c("fst","fld","city","city","fst","fld","fst","road","river","river","city","city","city"),
  species=c("blu","blu","pink","pink","pink","pink","pink","pink","pink","pink","pink","pink","pink"),
  day= c(34,87,93,79,56,98,100,187,54,14,63,57,23))

Answer 1

＆＃39; df＆＃39;是数据框架＆＃39;。它需要转换为data.table假设如果不进行转换，我会收到错误

Error in `[.data.frame`(df, , { : could not find function "."

使用data.table或setDT转换为as.data.table，可行

setDT(df)[,{
  r10s     <- 1:.N/.N < .1
  myrows   <- if(sum(r10s)>0){r10s}else{TRUE}
c(
   .SD[myrows],
  list(first10=mean(day[r10s]))
)
},.(species,year)]  
#   species year temp habitat day first10
#1:     blu 1901   29     fst  34     NaN
#2:     blu 1901   25     fld  87     NaN
#3:    pink 1901   21    city  93      93

R：data.table错误

1 个答案: