使用data.table时如何避免奇怪的变音错误

Question

考虑到ID,我需要在稀疏数据帧上运行求和

require(data.table)
sentEx = structure(list(abend = c(1, 1, 0, 0, 2), aber = c(0, 1, 0, 0, 
0), über = c(1, 0, 0, 0, 0), überall = c(0, 0, 0, 0, 0), überlegt = c(0, 
0, 0, 0, 0), ID = structure(c(1L, 1L, 2L, 2L, 2L), .Label = c("0019", 
"0021"), class = "factor"), abgeandert = c(1, 1, 1, 0, 0), abgebildet = c(0, 
0, 1, 1, 0), abgelegt = c(0, 0, 0, 0, 3)), .Names = c("abend", 
"aber", "über", "überall", "überlegt", "ID", "abgeandert", "abgebildet", 
"abgelegt"), row.names = c(1L, 2L, 16L, 17L, 18L), class = "data.frame")

sentEx  # How it looks
   abend aber über überall überlegt   ID abgeandert abgebildet abgelegt
1      1    0    1       0        0 0019          1          0        0
2      1    1    0       0        0 0019          1          0        0
16     0    0    0       0        0 0021          1          1        0
17     0    0    0       0        0 0021          0          1        0
18     2    0    0       0        0 0021          0          0        3

没有"破土动工"它可以正常工作:

sentEx.dt <- data.table(sentEx[,-c(3,4,5)])[, lapply(.SD, sum), by=ID]
(sentExSum <- as.data.frame(sentEx.dt))  # Need again as dataframe, which looks like:
    ID abend aber abgeandert abgebildet abgelegt
1 0019     2    1          2          0        0
2 0021     2    0          1          2        3 

但否则我得到这个错误:

sentEx.dt <- data.table(sentEx)[, lapply(.SD, sum), by=ID]
# Error in gsum(`über`) : object 'über' not found
      sentExSum <- as.data.frame(sentEx.dt)

一些额外的seeion信息(因为问题似乎与系统有关 - 请参阅注释):

sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=German_Germany.1252  LC_CTYPE=German_Germany.1252    LC_MONETARY=German_Germany.1252 LC_NUMERIC=C                   
[5] LC_TIME=German_Germany.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] data.table_1.9.2

loaded via a namespace (and not attached):
[1] plyr_1.8.1     Rcpp_0.11.0    reshape2_1.2.2 stringr_0.6.2  tools_3.0.2

还请求命令:

require(data.table); test.data.table()
Running C:/Users/Krohana/Documents/R/win-library/3.0/data.table/tests/tests.Rraw 
Loading required package: reshape
Loading required package: hexbin
Loading required package: xts
Loading required package: bit64
Test 167.2 not run. If required call library(hexbin) first.
Don't know how to automatically pick scale for object of type ITime. Defaulting to continuous
Don't know how to automatically pick scale for object of type ITime. Defaulting to continuous
Tests 487 and 488 not run. If required call library(reshape) first.
Test 841 not run. If required call library(xts) first.
Tests 897-899 not run. If required call library(bit64) first.
All 1220 tests in inst/tests/tests.Rraw completed ok in 24.321sec on Sun Mar 02 17:57:26 2014 ts/tests.Rraw completed ok in 24.638sec on Sun Mar 02 17:55:45 2014

请求的命令2:

> Encoding(names(sentEx))
[1] "unknown" "unknown" "UTF-8"   "UTF-8"   "UTF-8"   "unknown" "unknown" "unknown" "unknown"
> options(datatable.verbose=TRUE)
> options(datatable.verbose=TRUE); options(datatable.optimize=1L);

Answer 1

我也无法重现。但是，阿伦发现了另一个“未找到对象错误”，我希望也是这个错误。

现在在 v1.9.3 中，提交 1212。​​来自新闻：

o 在某些情况下，可能会出现错误“未找到对象 [名称]”，特别是在出现先前错误之后。报告列名中包含非 ASCII 字符，我们希望这只是为了转移注意力，因为 data.table 中的列名支持非 ASCII 字符。已实施修复并添加测试。

如果再次发生这种情况，请告诉我们。您的测试已逐字添加到测试套件中，谢谢。