Returns a string containing the first character of self
:
s = 'foo' # => "foo" s.chr # => "f"
Returns an array of the characters in self
:
'hello'.chars # => ["h", "e", "l", "l", "o"] 'тест'.chars # => ["т", "е", "с", "т"] 'こんにちは'.chars # => ["こ", "ん", "に", "ち", "は"]
Returns a new string copied from self
, with trailing characters possibly removed.
Removes "\r\n"
if those are the last two characters.
"abc\r\n".chop # => "abc" "тест\r\n".chop # => "тест" "こんにちは\r\n".chop # => "こんにちは"
Otherwise removes the last character if it exists.
'abcd'.chop # => "abc" 'тест'.chop # => "тес" 'こんにちは'.chop # => "こんにち" ''.chop # => ""
If you only need to remove the newline separator at the end of the string, String#chomp
is a better alternative.
Returns a new string copied from self
, with trailing characters possibly removed:
When line_sep
is "\n"
, removes the last one or two characters if they are "\r"
, "\n"
, or "\r\n"
(but not "\n\r"
):
$/ # => "\n" "abc\r".chomp # => "abc" "abc\n".chomp # => "abc" "abc\r\n".chomp # => "abc" "abc\n\r".chomp # => "abc\n" "тест\r\n".chomp # => "тест" "こんにちは\r\n".chomp # => "こんにちは"
When line_sep
is ''
(an empty string), removes multiple trailing occurrences of "\n"
or "\r\n"
(but not "\r"
or "\n\r"
):
"abc\n\n\n".chomp('') # => "abc" "abc\r\n\r\n\r\n".chomp('') # => "abc" "abc\n\n\r\n\r\n\n\n".chomp('') # => "abc" "abc\n\r\n\r\n\r".chomp('') # => "abc\n\r\n\r\n\r" "abc\r\r\r".chomp('') # => "abc\r\r\r"
When line_sep
is neither "\n"
nor ''
, removes a single trailing line separator if there is one:
'abcd'.chomp('d') # => "abc" 'abcdd'.chomp('d') # => "abcd"
Like String#chop
, but modifies self
in place; returns nil
if self
is empty, self
otherwise.
Related: String#chomp!
.
Like String#chomp
, but modifies self
in place; returns nil
if no modification made, self
otherwise.
Returns the Fiber
scheduler, that was last set for the current thread with Fiber.set_scheduler
. Returns nil
if no scheduler is set (which is the default), and non-blocking fibers’ behavior is the same as blocking. (see “Non-blocking fibers” section in class docs for details about the scheduler concept).
The method is expected to immediately run the provided block of code in a separate non-blocking fiber.
puts "Go to sleep!" Fiber.set_scheduler(MyScheduler.new) Fiber.schedule do puts "Going to sleep" sleep(1) puts "I slept well" end puts "Wakey-wakey, sleepyhead"
Assuming MyScheduler is properly implemented, this program will produce:
Go to sleep! Going to sleep Wakey-wakey, sleepyhead ...1 sec pause here... I slept well
…e.g. on the first blocking operation inside the Fiber
(sleep(1)
), the control is yielded to the outside code (main fiber), and at the end of that execution, the scheduler takes care of properly resuming all the blocked fibers.
Note that the behavior described above is how the method is expected to behave, actual behavior is up to the current scheduler’s implementation of Fiber::Scheduler#fiber
method. Ruby doesn’t enforce this method to behave in any particular way.
If the scheduler is not set, the method raises RuntimeError (No scheduler is available!)
.
Returns true if path
matches against pattern
. The pattern is not a regular expression; instead it follows rules similar to shell filename globbing. It may contain the following metacharacters:
*
Matches any file. Can be restricted by other values in the glob. Equivalent to /.*/x
in regexp.
*
Matches all regular files
c*
Matches all files beginning with c
*c
Matches all files ending with c
*c*
Matches all files that have c
in them (including at the beginning or end).
To match hidden files (that start with a .
) set the File::FNM_DOTMATCH flag.
**
Matches directories recursively or files expansively.
?
Matches any one character. Equivalent to /.{1}/
in regexp.
[set]
Matches any one character in set
. Behaves exactly like character sets in Regexp
, including set negation ([^a-z]
).
\
Escapes the next metacharacter.
{a,b}
Matches pattern a and pattern b if File::FNM_EXTGLOB flag is enabled. Behaves like a Regexp
union ((?:a|b)
).
flags
is a bitwise OR of the FNM_XXX
constants. The same glob pattern and flags are used by Dir::glob
.
Examples:
File.fnmatch('cat', 'cat') #=> true # match entire string File.fnmatch('cat', 'category') #=> false # only match partial string File.fnmatch('c{at,ub}s', 'cats') #=> false # { } isn't supported by default File.fnmatch('c{at,ub}s', 'cats', File::FNM_EXTGLOB) #=> true # { } is supported on FNM_EXTGLOB File.fnmatch('c?t', 'cat') #=> true # '?' match only 1 character File.fnmatch('c??t', 'cat') #=> false # ditto File.fnmatch('c*', 'cats') #=> true # '*' match 0 or more characters File.fnmatch('c*t', 'c/a/b/t') #=> true # ditto File.fnmatch('ca[a-z]', 'cat') #=> true # inclusive bracket expression File.fnmatch('ca[^t]', 'cat') #=> false # exclusive bracket expression ('^' or '!') File.fnmatch('cat', 'CAT') #=> false # case sensitive File.fnmatch('cat', 'CAT', File::FNM_CASEFOLD) #=> true # case insensitive File.fnmatch('cat', 'CAT', File::FNM_SYSCASE) #=> true or false # depends on the system default File.fnmatch('?', '/', File::FNM_PATHNAME) #=> false # wildcard doesn't match '/' on FNM_PATHNAME File.fnmatch('*', '/', File::FNM_PATHNAME) #=> false # ditto File.fnmatch('[/]', '/', File::FNM_PATHNAME) #=> false # ditto File.fnmatch('\?', '?') #=> true # escaped wildcard becomes ordinary File.fnmatch('\a', 'a') #=> true # escaped ordinary remains ordinary File.fnmatch('\a', '\a', File::FNM_NOESCAPE) #=> true # FNM_NOESCAPE makes '\' ordinary File.fnmatch('[\?]', '?') #=> true # can escape inside bracket expression File.fnmatch('*', '.profile') #=> false # wildcard doesn't match leading File.fnmatch('*', '.profile', File::FNM_DOTMATCH) #=> true # period by default. File.fnmatch('.*', '.profile') #=> true File.fnmatch('**/*.rb', 'main.rb') #=> false File.fnmatch('**/*.rb', './main.rb') #=> false File.fnmatch('**/*.rb', 'lib/song.rb') #=> true File.fnmatch('**.rb', 'main.rb') #=> true File.fnmatch('**.rb', './main.rb') #=> false File.fnmatch('**.rb', 'lib/song.rb') #=> true File.fnmatch('*', 'dave/.profile') #=> true File.fnmatch('**/foo', 'a/b/c/foo', File::FNM_PATHNAME) #=> true File.fnmatch('**/foo', '/a/b/c/foo', File::FNM_PATHNAME) #=> true File.fnmatch('**/foo', 'c:/a/b/c/foo', File::FNM_PATHNAME) #=> true File.fnmatch('**/foo', 'a/.b/c/foo', File::FNM_PATHNAME) #=> false File.fnmatch('**/foo', 'a/.b/c/foo', File::FNM_PATHNAME | File::FNM_DOTMATCH) #=> true
Changes permission bits on the named file(s) to the bit pattern represented by mode_int. Actual effects are operating system dependent (see the beginning of this section). On Unix systems, see chmod(2)
for details. Returns the number of files processed.
File.chmod(0644, "testfile", "out") #=> 2
Changes the owner and group of the named file(s) to the given numeric owner and group id’s. Only a process with superuser privileges may change the owner of a file. The current owner of a file may change the file’s group to any group to which the owner belongs. A nil
or -1 owner or group id is ignored. Returns the number of files processed.
File.chown(nil, 100, "testfile")
Equivalent to File::chmod
, but does not follow symbolic links (so it will change the permissions associated with the link, not the file referenced by the link). Often not available.
Equivalent to File::chown
, but does not follow symbolic links (so it will change the owner associated with the link, not the file referenced by the link). Often not available. Returns number of files in the argument list.
Changes permission bits on file to the bit pattern represented by mode_int. Actual effects are platform dependent; on Unix systems, see chmod(2)
for details. Follows symbolic links. Also see File#lchmod.
f = File.new("out", "w"); f.chmod(0644) #=> 0
Changes the owner and group of file to the given numeric owner and group id’s. Only a process with superuser privileges may change the owner of a file. The current owner of a file may change the file’s group to any group to which the owner belongs. A nil
or -1 owner or group id is ignored. Follows symbolic links. See also File#lchown.
File.new("testfile").chown(502, 1000)
Returns true
if filepath
points to a character device, false
otherwise.
File.chardev?($stdin) # => true File.chardev?('t.txt') # => false
Iterates over the block according to how this Enumerator
was constructed. If no block and no arguments are given, returns self.
"Hello, world!".scan(/\w+/) #=> ["Hello", "world"] "Hello, world!".to_enum(:scan, /\w+/).to_a #=> ["Hello", "world"] "Hello, world!".to_enum(:scan).each(/\w+/).to_a #=> ["Hello", "world"] obj = Object.new def obj.each_arg(a, b=:b, *rest) yield a yield b yield rest :method_returned end enum = obj.to_enum :each_arg, :a, :x enum.each.to_a #=> [:a, :x, []] enum.each.equal?(enum) #=> true enum.each { |elm| elm } #=> :method_returned enum.each(:y, :z).to_a #=> [:a, :x, [:y, :z]] enum.each(:y, :z).equal?(enum) #=> false enum.each(:y, :z) { |elm| elm } #=> :method_returned
Return the matchee associated with this NoMatchingPatternKeyError
exception.
Returns a hash of values parsed from string
, which should be a valid XML date format:
d = Date.new(2001, 2, 3) s = d.xmlschema # => "2001-02-03" Date._xmlschema(s) # => {:year=>2001, :mon=>2, :mday=>3}
See argument limit.
Related: Date.xmlschema
(returns a Date object).
Returns a new Date object with values parsed from string
, which should be a valid XML date format:
d = Date.new(2001, 2, 3) s = d.xmlschema # => "2001-02-03" Date.xmlschema(s) # => #<Date: 2001-02-03>
See:
Argument start.
Argument limit.
Related: Date._xmlschema
(returns a hash).
Equivalent to strftime
with argument '%Y-%m-%d'
(or its shorthand form '%F'
);
Date.new(2001, 2, 3).iso8601 # => "2001-02-03"
Creates a new DateTime
object by parsing from a string according to some typical XML Schema formats.
DateTime.xmlschema('2001-02-03T04:05:06+07:00') #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
Raise an ArgumentError
when the string length is longer than limit. You can stop this check by passing limit: nil
, but note that it may take a long time to parse.
This method is equivalent to strftime(‘%FT%T%:z’). The optional argument n
is the number of digits for fractional seconds.
DateTime.parse('2001-02-03T04:05:06.123456789+07:00').iso8601(9) #=> "2001-02-03T04:05:06.123456789+07:00"
Parses time
as a dateTime defined by the XML Schema and converts it to a Time
object. The format is a restricted version of the format defined by ISO 8601.
ArgumentError
is raised if time
is not compliant with the format or if the Time
class cannot represent the specified time.
See xmlschema
for more information on this format.
require 'time' Time.xmlschema("2011-10-05T22:26:12-04:00") #=> 2011-10-05 22:26:12-04:00
You must require ‘time’ to use this method.