nchar takes a character vector as an argument and
returns a vector whose elements contain the sizes of
the corresponding elements of x. nzchar is a fast way to find out if elements of a character
vector are non-empty strings.
nchar(x, type = "chars", allowNA = FALSE, keepNA = FALSE)
nzchar(x, keepNA = FALSE)c("bytes", "chars", "width"). See ‘Details’.NA be returned for invalid
multibyte strings or "bytes"-encoded strings (rather than
throwing an error)?NA be returned where ever
x is NA? If false, the (implicit or explicit)
default for nzchar() and for R versions $<=$ 3.2.x,="" 2, as that is the number of printing
characters used when strings are written to output, and
nzchar() is TRUE.
From R version 3.3.0 on, for nchar() only, the default will
be NA, which means to use keepNA = TRUE unless
type is "width". Used to be (implicitly) hard coded
to FALSE in R versions $nchar, an integer vector giving the sizes of each element.
For missing values (i.e., NA, i.e., NA_character_),
nchar() returns NA_integer_ if keepNA is
true, and 2, the number of printing characters, if false.type = "width" gives (an approximation to) the number of
columns used in printing each element in a terminal font, taking into
account double-width, zero-width and ‘composing’ characters.If allowNA = TRUE and an element is detected as invalid in a
multi-byte character set such as UTF-8, its number of characters and
the width will be NA. Otherwise the number of characters will
be non-negative, so !is.na(nchar(x, "chars", TRUE)) is a test
of validity.A character string marked with "bytes" encoding (see
Encoding) has a number of bytes, but neither a known
number of characters nor a width, so the latter two types are
NA if allowNA = TRUE, otherwise an error.Names, dims and dimnames are copied from the input.For nzchar, a logical vector of the same length as x,
true if and only if the element has non-zero length; if the element is
NA, nzchar() is true when keepNA is false, as by
default, and NA otherwise.
type argument):
bytes
chars
widthcat will use to
print the string in a monospaced font. The same as chars
if this cannot be calculated.
These will often be the same, and almost always will be in single-byte
locales (but note how type may influence NA treatment
for keepNA = NA). There will be differences between the first two with
multibyte character sequences, e.g.\ifelse{latex}{\out{~}}{ } in UTF-8 locales.
The internal equivalent of the default method of
as.character is performed on x (so there is no
method dispatch). If you want to operate on non-vector objects
passing them through deparse first will be required.
strwidth giving width of strings for plotting;
paste, substr, strsplit
x <- c("asfef", "qwerty", "yuiop[", "b", "stuff.blah.yech")
nchar(x)
# 5 6 6 1 15
nchar(deparse(mean))
# 18 17 <-- unless mean differs from base::mean
x[3] <- NA; x
nchar(x, keepNA= TRUE) # 5 6 NA 1 15
nchar(x, keepNA=FALSE) # 5 6 2 1 15
stopifnot(identical(nchar(x, "w", keepNA = NA),
nchar(x, keepNA = FALSE)),
identical(is.na(x), is.na(nchar(x, keepNA=NA))))
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