Re:as.Date() is strange

奥華子いいですよね

x <- "2012年10月3<e6>
y1 <- "2012年10月3<e6>

identical(x, y1)

## [1] TRUE

print(as.Date(x = x, format = "%Y年%m月%d日

## [1] "2012-10-03"

print(as.Date(x = y1, format = "%Y年%m月%d日

## [1] "2012-10-03"

追記：環境こんな感じです。

sessionInfo()

## R version 2.15.0 (2012-03-30)
## Platform: x86_64-pc-mingw32/x64 (64-bit)
## 
## locale:
## [1] LC_COLLATE=Japanese_Japan.932  LC_CTYPE=Japanese_Japan.932   
## [3] LC_MONETARY=Japanese_Japan.932 LC_NUMERIC=C                  
## [5] LC_TIME=Japanese_Japan.932    
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] knitr_0.5
## 
## loaded via a namespace (and not attached):
##  [1] codetools_0.2-8 digest_0.5.2    evaluate_0.4.2  formatR_0.4    
##  [5] highlight_0.2-5 parser_0.0-14   plyr_1.7.1      Rcpp_0.9.10    
##  [9] stringr_0.6     tools_2.15.0