如何在R Windows中将Unicode字符串写入文本文件？

这是一个扩展示例,用于演示我认为在原始示例中发生的情况：

print_info <- function(x) {
    print(x)
    print(Encoding(x))
    str(x)
    print(charToRaw(x))
}

cat("(1) Original string (UTF-8)n")
str <- "xe1xbbx8f"
Encoding(str) <- "UTF-8"
print_info(str)
cat(str,file="no-iconv")

cat("n(2) Conversion to UTF-8,wrong input encoding (latin1)n")
## from = "" is conversion from current locale,forcing "latin1" here
str2 <- iconv(str,from="latin1",to="UTF-8")
print_info(str2)
cat(str2,file="yes-iconv")

cat("n(3) Converting (2) explicitly to latin1n")
str3 <- iconv(str2,from="UTF-8",to="latin1")
print_info(str3)
cat(str3,file="latin")

cat("n(4) Setting encoding of (1) to "unknown"n")
str4 <- str
Encoding(str4) <- "unknown"
print_info(str4)
cat(str4,file="unknown")

在Windows上的R使用的“Latin-1”语言环境(参见？l10n_info)中,输出文件“yes-iconv”,“latin”和“unknown”应该是正确的(字节序列0xe1,0xbb,0x8f是“?” “).

在“UTF-8”语言环境中,文件“no-iconv”和“unknown”应该是正确的.

示例代码的输出如下,使用在Wine上运行的R 3.3.2 64位Windows版本：

(1) Original string (UTF-8)
[1] "?"
[1] "UTF-8"
 chr "<U+1ECF>""| __truncated__
[1] e1 bb 8f

(2) Conversion to UTF-8,wrong input encoding (latin1)
[1] "á?u008f"
[1] "UTF-8"
 chr "á?u008f"
[1] c3 a1 c2 bb c2 8f

(3) Converting (2) explicitly to latin1
[1] "á?"
[1] "latin1"
 chr "á?"
[1] e1 bb 8f

(4) Setting encoding of (1) to "unknown"
[1] "á?"
[1] "unknown"
 chr "á?"
[1] e1 bb 8f

在原始示例中,iconv()使用默认的from =“”参数,这意味着从当前语言环境转换,这实际上是“latin1”.因为str的编码实际上是“UTF-8”,所以字符串的字节表示在步骤(2)中失真,但是当它(可能)将字符串转换回当前语言环境时,由cat()隐式恢复,如通过步骤(3)中的等效转换证明了这一点.