Function to do wildcard expansion (also known as ‘globbing’) on file paths.
character vector of patterns for relative or absolute filepaths. Missing values will be ignored.
logical: should matches to directories from patterns
that do not already end in
This expands tilde (see tilde expansion) and wildcards in file paths.
For precise details of wildcards expansion, see your
system's documentation on the
glob system call. There is a
POSIX 1003.2 standard (see
but some OSes will go beyond this.
All systems should interpret
* (match zero or more characters),
? (match a single character) and (probably)
[ (begin a
character class or range). The handling of paths
ending with a separator is system-dependent. On a POSIX-2008
compliant OS they will match directories (only), but as they are not
valid filepaths on Windows, they match nothing there. (Earlier POSIX
standards allowed them to match files.)
The rest of these details are indicative (and based on the POSIX standard).
If a filename starts with
. this may need to be matched
explicitly: for example
Sys.glob("*.RData") may or may not
match ‘.RData’ but will not usually match ‘.aa.RData’. Note
that this is platform-dependent: e.g. on Solaris
Sys.glob("*.*") matches ‘.’ and ‘..’.
[ begins a character class. If the first character in
[...] is not
!, this is a character class which matches
a single character against any of the characters specified. The class
cannot be empty, so
] can be included provided it is first. If
the first character is
!, the character class matches a single
character which is none of the specified characters. Whether
. in a character class matches a leading
. in the
filename is OS-dependent.
Character classes can include ranges such as
- as a character by having it first or last in a class. (The
interpretation of ranges should be locale-specific, so the example is
not a good idea in an Estonian locale.)
One can remove the special meaning of
[ by preceding them by a backslash (except within a
A character vector of matched file paths. The order is
system-specific (but in the order of the elements of
is normally collated in either the current locale or in byte (ASCII)
order; however, on Windows collation is in the order of Unicode
Directory errors are normally ignored, so the matches are to accessible file paths (but not necessarily accessible files).
Quotes for handling backslashes in character strings.
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