Centers str
in width
. If width
is greater than the length of str
, returns a new String of length width
with str
centered and padded with padstr
; otherwise, returns str
.
"hello".center(4) #=> "hello" "hello".center(20) #=> " hello " "hello".center(20, '123') #=> "1231231hello12312312"
Returns a new String
with the last character removed. If the string ends with \r\n
, both characters are removed. Applying chop
to an empty string returns an empty string. String#chomp
is often a safer alternative, as it leaves the string unchanged if it doesn’t end in a record separator.
"string\r\n".chop #=> "string" "string\n\r".chop #=> "string\n" "string\n".chop #=> "string" "string".chop #=> "strin" "x".chop.chop #=> ""
Returns a copy of str with trailing whitespace removed. See also String#lstrip
and String#strip
.
Refer to strip
for the definition of whitespace.
" hello ".rstrip #=> " hello" "hello".rstrip #=> "hello"
Processes str as for String#chop
, returning str, or nil
if str is the empty string. See also String#chomp!
.
Removes trailing whitespace from str, returning nil
if no change was made. See also String#lstrip!
and String#strip!
.
Refer to strip
for the definition of whitespace.
" hello ".rstrip #=> " hello" "hello".rstrip! #=> nil
Returns 0 if the value is positive, pi otherwise.
Returns 0 if the value is positive, pi otherwise.
provides a unified clone
operation, for REXML::XPathParser
to use across multiple Object
types
Returns an array with both a numeric
and a float
represented as Float
objects.
This is achieved by converting a numeric
to a Float
.
1.2.coerce(3) #=> [3.0, 1.2] 2.5.coerce(1.1) #=> [1.1, 2.5]
Returns true
if float
is 0.0.
Returns true
if float
is greater than 0.
Returns true
if float
is less than 0.
Returns the numerator. The result is machine dependent.
n = 0.3.numerator #=> 5404319552844595 d = 0.3.denominator #=> 18014398509481984 n.fdiv(d) #=> 0.3
Transfer control to another fiber, resuming it from where it last stopped or starting it if it was not resumed before. The calling fiber will be suspended much like in a call to Fiber.yield
. You need to require 'fiber'
before using this method.
The fiber which receives the transfer call is treats it much like a resume call. Arguments passed to transfer are treated like those passed to resume.
You cannot resume a fiber that transferred control to another one. This will cause a double resume error. You need to transfer control back to this fiber before it can yield and resume.
Example:
fiber1 = Fiber.new do puts "In Fiber 1" Fiber.yield end fiber2 = Fiber.new do puts "In Fiber 2" fiber1.transfer puts "Never see this message" end fiber3 = Fiber.new do puts "In Fiber 3" end fiber2.resume fiber3.resume
produces
In fiber 2 In fiber 1 In fiber 3
The optional enc argument specifies the encoding of the directory. If not specified, the filesystem encoding is used.
With no block, open
is a synonym for Dir::new
. If a block is present, it is passed aDir as a parameter. The directory is closed at the end of the block, and Dir::open
returns the value of the block.
Seeks to a particular location in dir. integer must be a value returned by Dir#tell
.
d = Dir.new("testdir") #=> #<Dir:0x401b3c40> d.read #=> "." i = d.tell #=> 12 d.read #=> ".." d.seek(i) #=> #<Dir:0x401b3c40> d.read #=> ".."
Closes the directory stream. Calling this method on closed Dir
object is ignored since Ruby 2.3.
d = Dir.new("testdir") d.close #=> nil
Returns the last access time for the named file as a Time
object).
file_name can be an IO
object.
File.atime("testfile") #=> Wed Apr 09 08:51:48 CDT 2003
Returns the modification time for the named file as a Time
object.
file_name can be an IO
object.
File.mtime("testfile") #=> Tue Apr 08 12:58:04 CDT 2003
Returns the change time for the named file (the time at which directory information about the file was changed, not the file itself).
file_name can be an IO
object.
Note that on Windows (NTFS), returns creation time (birth time).
File.ctime("testfile") #=> Wed Apr 09 08:53:13 CDT 2003
Returns the birth time for the named file.
file_name can be an IO
object.
File.birthtime("testfile") #=> Wed Apr 09 08:53:13 CDT 2003
If the platform doesn’t have birthtime, raises NotImplementedError
.
Sets the access and modification times of each named file to the first two arguments. Returns the number of file names in the argument list.
Returns the real (absolute) pathname of pathname in the actual filesystem not containing symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
All components of the pathname must exist when this method is called.
Returns the real (absolute) pathname of pathname in the actual filesystem. The real pathname doesn’t contain symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
The last component of the real pathname can be nonexistent.