Maintenance Ruby 3.4 gets fixes, but no new features. Switch to Ruby 4.0 →
class method
File.extname
(::string | ::_ToPath path) -> ::String
File.extname(path) → string
file.c
View on GitHub ↗
static VALUE
rb_file_s_extname(VALUE klass, VALUE fname)
{
const char *name, *e;
long len;
VALUE extname;
FilePathStringValue(fname);
name = StringValueCStr(fname);
len = RSTRING_LEN(fname);
e = ruby_enc_find_extname(name, &len, rb_enc_get(fname));
if (len < 1)
return rb_str_new(0, 0);
extname = rb_str_subseq(fname, e - name, len); /* keep the dot, too! */
return extname;
}
Returns the extension (the portion of file name in path starting from the last period).
If path is a dotfile, or starts with a period, then the starting dot is not dealt with the start of the extension.
An empty string will also be returned when the period is the last character in path.
On Windows, trailing dots are truncated.
Example
File.extname("test.rb") #=> ".rb" File.extname("a/b/d/test.rb") #=> ".rb" File.extname(".a/b/d/test.rb") #=> ".rb" File.extname("foo.") #=> "" on Windows File.extname("foo.") #=> "." on non-Windows File.extname("test") #=> "" File.extname(".profile") #=> "" File.extname(".profile.sh") #=> ".sh"