R - 重塑 - 融化錯誤

Question

我想融化一個數據框，並得到這個奇怪的錯誤。任何想法爲什麼？

str(zx7) 
'data.frame': 519 obs. of 5 variables: 
$ calday.new: Date, format: "2011-01-03" "2011-01-04" "2011-01-05" "2011-01-06" ... 
$ A20 : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ B20 : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ C20 : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ D20 : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 

zx7.melt <- melt(zx7, id=c("calday.new")) 
Error in `[<-.ts`(`*tmp*`, ri, value = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, : only replacement of elements is allowed 

Answer 1

我卻不知道你是如何創建的結構，但我這樣做的時候，我的作品

zx7 <- data.frame(calday.new=seq(from = as.Date('2011-01-03'),by=1,length.out=519), 
        A20=ts(rep(0,519)), 
        B20=ts(rep(0,519)), 
        C20=ts(rep(0,519)), 
        D20=ts(rep(0,519))) 

我創建相同的結構如上：

str(zx7) 
'data.frame': 519 obs. of 5 variables: 
$ calday.new: Date, format: "2011-01-03" "2011-01-04" "2011-01-05" ... 
$ A20  : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ B20  : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ C20  : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 
$ D20  : Time-Series from 1 to 519: 0 0 0 0 0 0 0 0 0 0 ... 

然後我融化：

head(melt(zx7, id=c("calday.new"))) 
    calday.new variable value 
1 2011-01-03  A20  0 
2 2011-01-04  A20  0 
3 2011-01-05  A20  0 
4 2011-01-06  A20  0 
5 2011-01-07  A20  0 
6 2011-01-08  A20  0 

Answer 2

問題是： t舊的「重塑」包melt()函數在遇到類ts的對象時不知道該怎麼做。

所以，你有兩個明顯的選擇（儘管可能有更多）：

1. unclass當前歸類爲ts你以前melt()數據的變量：

   zx7b <- zx7   # Make a backup, just in case 
   library(reshape) # Notice this is "reshape", not "reshape2" 
   head(melt(zx7b, id=c("calday.new"))) # Doesn't work 
   # Error in `[<-.ts`(`*tmp*`, ri, value = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, : 
   # only replacement of elements is allowed 
   
   ## Unclass the relevant columns from your data.frame 
   zx7b[sapply(zx7b, is.ts)] <- lapply(zx7b[sapply(zx7b, is.ts)], 
               unclass) 
   head(melt(zx7b, id=c("calday.new"))) 
   # calday.new variable value 
   # 1 2011-01-03  A20  0 
   # 2 2011-01-04  A20  0 
   # 3 2011-01-05  A20  0 
   # 4 2011-01-06  A20  0 
   # 5 2011-01-07  A20  0 
   # 6 2011-01-08  A20  0 
   

2. 升級而不是「reshape2」，並且不需要unclassing。

   library(reshape2) # Notice that this is reshape2! 
   head(melt(zx7, id=c("calday.new"))) # Melt the original data.frame 
   # calday.new variable value 
   # 1 2011-01-03  A20  0 
   # 2 2011-01-04  A20  0 
   # 3 2011-01-05  A20  0 
   # 4 2011-01-06  A20  0 
   # 5 2011-01-07  A20  0 
   # 6 2011-01-08  A20  0 
   

我還沒有花時間去做，但你可以從「重塑」包的每個版本檢查爲melt.data.frame方法的代碼爲melt()，看看那裏的差別所在。安裝這兩個軟件包，然後鍵入reshape2:::melt.data.frame和reshape:::melt.data.frame以查看基本功能。