Returns a new array with elements of self shuffled.
a = [ 1, 2, 3 ] #=> [1, 2, 3] a.shuffle #=> [2, 3, 1] a #=> [1, 2, 3]
The optional rng argument will be used as the random number generator.
a.shuffle(random: Random.new(1)) #=> [1, 3, 2]
Choose a random element or n random elements from the array.
The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn’t repeat itself unless the array already contained duplicate elements.
If the array is empty the first form returns nil and the second form returns an empty array.
The optional rng argument will be used as the random number generator.
a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] a.sample #=> 7 a.sample(4) #=> [6, 4, 2, 5]
Calls the given block for each element n times or forever if nil is given.
Does nothing if a non-positive number is given or the array is empty.
Returns nil if the loop has finished without getting interrupted.
If no block is given, an Enumerator is returned instead.
a = ["a", "b", "c"] a.cycle { |x| puts x } # print, a, b, c, a, b, c,.. forever. a.cycle(2) { |x| puts x } # print, a, b, c, a, b, c.
Returns true if big is an odd number.
Returns the angle part of its polar form.
Complex.polar(3, Math::PI/2).arg #=> 1.5707963267948966
Returns 0 if the value is positive, pi otherwise.
Convert self to locale encoding
Escapes str so that it can be safely used in a Bourne shell command line.
See Shellwords.shellescape for details.
Returns the character length of str.
Produces a version of str with all non-printing characters replaced by \nnn notation and all special characters escaped.
"hello \n ''".dump #=> "\"hello \\n ''\"
Returns an array of the Integer ordinals of the characters in str. This is a shorthand for str.each_codepoint.to_a.
If a block is given, which is a deprecated form, works the same as each_codepoint.
Returns a copy of str with all characters in the intersection of its arguments deleted. Uses the same rules for building the set of characters as String#count.
"hello".delete "l","lo" #=> "heo" "hello".delete "lo" #=> "he" "hello".delete "aeiou", "^e" #=> "hell" "hello".delete "ej-m" #=> "ho"
Performs a delete operation in place, returning str, or nil if str was not modified.
Returns 0 if the value is positive, pi otherwise.
Returns the file descriptor used in dir.
d = Dir.new("..") d.fileno #=> 8
This method uses dirfd() function defined by POSIX 2008. NotImplementedError is raised on other platforms, such as Windows, which doesn’t provide the function.
Deletes the named directory. Raises a subclass of SystemCallError if the directory isn’t empty.
Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. See also Dir::rmdir.
Returns true if the named file is readable by the effective user and group id of this process. See eaccess(3).
Returns true if the named file is writable by the effective user and group id of this process. See eaccess(3).
Returns true if the named file is executable by the effective user and group id of this process. See eaccess(3).
Returns true if the named file exists and is a regular file.
file can be an IO object.
If the file argument is a symbolic link, it will resolve the symbolic link and use the file referenced by the link.
Returns true for dummy encodings. A dummy encoding is an encoding for which character handling is not properly implemented. It is used for stateful encodings.
Encoding::ISO_2022_JP.dummy? #=> true Encoding::UTF_8.dummy? #=> false
Returns the return value of the iterator.
o = Object.new def o.each yield 1 yield 2 yield 3 100 end e = o.to_enum puts e.next #=> 1 puts e.next #=> 2 puts e.next #=> 3 begin e.next rescue StopIteration => ex puts ex.result #=> 100 end
The primary interface to this library. Use to setup delegation when defining your class.
class MyClass < DelegateClass(ClassToDelegateTo) # Step 1 def initialize super(obj_of_ClassToDelegateTo) # Step 2 end end
Here’s a sample of use from Tempfile which is really a File object with a few special rules about storage location and when the File should be deleted. That makes for an almost textbook perfect example of how to use delegation.
class Tempfile < DelegateClass(File) # constant and class member data initialization... def initialize(basename, tmpdir=Dir::tmpdir) # build up file path/name in var tmpname... @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600) # ... super(@tmpfile) # below this point, all methods of File are supported... end # ... end