Sets the payload of the vertex with the given name @param [String] name the name of the vertex @param [Object] payload the payload @return [Void]
Search for the specifications that match the given dependency. The specifications in the returned array will be considered in reverse order, so the latest version ought to be last. @note This method should be ‘pure’, i.e. the return value should depend
only on the `dependency` parameter.
@param [Object] dependency @return [Array<Object>] the specifications that satisfy the given
`dependency`.
Adds this spec’s require paths to LOAD_PATH, in the proper location.
Returns self
.
Drops elements up to, but not including, the first element for which the block returns nil
or false
and returns an array containing the remaining elements.
If no block is given, an Enumerator
is returned instead.
See also Array#take_while
a = [1, 2, 3, 4, 5, 0] a.drop_while {|i| i < 3 } #=> [3, 4, 5, 0]
Returns the singleton class of obj. This method creates a new singleton class if obj does not have one.
If obj is nil
, true
, or false
, it returns NilClass
, TrueClass
, or FalseClass
, respectively. If obj is an Integer
, a Float
or a Symbol
, it raises a TypeError
.
Object.new.singleton_class #=> #<Class:#<Object:0xb7ce1e24>> String.singleton_class #=> #<Class:String> nil.singleton_class #=> NilClass
Yields self to the block and returns the result of the block.
3.next.then {|x| x**x }.to_s #=> "256" "my string".yield_self {|s| s.upcase } #=> "MY STRING"
Good usage for then
is value piping in method chains:
require 'open-uri' require 'json' construct_url(arguments). then {|url| open(url).read }. then {|response| JSON.parse(response) }
When called without block, the method returns Enumerator
, which can be used, for example, for conditional circuit-breaking:
# meets condition, no-op 1.then.detect(&:odd?) # => 1 # does not meet condition, drop value 2.then.detect(&:odd?) # => nil
Returns an array of the names of singleton methods for obj. If the optional all parameter is true, the list will include methods in modules included in obj. Only public and protected singleton methods are returned.
module Other def three() end end class Single def Single.four() end end a = Single.new def a.one() end class << a include Other def two() end end Single.singleton_methods #=> [:four] a.singleton_methods(false) #=> [:two, :one] a.singleton_methods #=> [:two, :one, :three]
Returns an array of instance variable names for the receiver. Note that simply defining an accessor does not create the corresponding instance variable.
class Fred attr_accessor :a1 def initialize @iv = 3 end end Fred.new.instance_variables #=> [:@iv]
Similar to method, searches singleton method only.
class Demo def initialize(n) @iv = n end def hello() "Hello, @iv = #{@iv}" end end k = Demo.new(99) def k.hi "Hi, @iv = #{@iv}" end m = k.singleton_method(:hi) m.call #=> "Hi, @iv = 99" m = k.singleton_method(:hello) #=> NameError
Invokes the method identified by symbol, passing it any arguments specified. Unlike send, public_send
calls public methods only. When the method is identified by a string, the string is converted to a symbol.
1.public_send(:puts, "hello") # causes NoMethodError
Returns true
if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true
.
If the method is not implemented, as Process.fork
on Windows, File.lchmod
on GNU/Linux, etc., false is returned.
If the method is not defined, respond_to_missing?
method is called and the result is returned.
When the method name parameter is given as a string, the string is converted to a symbol.
Returns a hash, that will be turned into a JSON
object and represent this object.
Returns true if str
starts with one of the prefixes
given. Each of the prefixes
should be a String
or a Regexp
.
"hello".start_with?("hell") #=> true "hello".start_with?(/H/i) #=> true # returns true if one of the prefixes matches. "hello".start_with?("heaven", "hell") #=> true "hello".start_with?("heaven", "paradise") #=> false
Passes each character in str to the given block, or returns an enumerator if no block is given.
"hello".each_char {|c| print c, ' ' }
produces:
h e l l o
Returns true for a string which has only ASCII characters.
"abc".force_encoding("UTF-8").ascii_only? #=> true "abc\u{6666}".force_encoding("UTF-8").ascii_only? #=> false
Returns the path parameter passed to dir’s constructor.
d = Dir.new("..") d.path #=> ".."