[R] nchar(type = "chars") of "latin1" string in C locale
mikko.korpela at helsinki.fi
Fri Feb 24 15:57:54 CET 2017
When running R in an ASCII locale (export LC_ALL=C) on Linux, is this
foo <- "\xe4"
Encoding(foo) <- "latin1"
#  "<e4>"
#  4
nchar(foo, type = "bytes")
#  1
nchar(foo, type = "width")
#  4
That is, the number of characters reported for the default 'type =
"chars"' is the number of characters (4) used for printing the unknown byte.
Obviously, one byte is one character in the single-byte ISO-8859-1
"latin1" encoding. Therefore I think the result of 4 characters for 1
byte is wrong, or unintuitive.
If this is as expected, maybe it should be mentioned in the '?nchar'
manual as a special case. Yes, I did try to read the manual for an
explanation. According to the manual, the result should be "The number
of human-readable characters", but there is the note that:
This does *not* by default give the number of characters that will
be used to 'print()' the string. Use 'encodeString' to find that.
For UTF-8 strings, nchar() does work correctly (as documented) even in
the C locale.
foo2 <- "\xc3\xa4"
Encoding(foo2) <- "UTF-8"
#  "<U+00E4>"
#  1
nchar(foo2, type = "bytes")
#  2
nchar(foo2, type = "width")
#  1
But, confusingly, encodeString() does not agree with print(), contrary
to the document '?encodeString':
#  "\\u00e4"
I was using "R Under development (unstable) (2017-02-23 r72248)".
Department of Geosciences and Geography
University of Helsinki
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