Results for: "String#[]"

Sets the priority of thr to integer. Higher-priority threads will run more frequently than lower-priority threads (but lower-priority threads can also run).

This is just hint for Ruby thread scheduler. It may be ignored on some platform.

count1 = count2 = 0
a = Thread.new do
      loop { count1 += 1 }
    end
a.priority = -1

b = Thread.new do
      loop { count2 += 1 }
    end
b.priority = -2
sleep 1   #=> 1
count1    #=> 622504
count2    #=> 5832

Equivalent to:

io.write(sprintf(format_string, *objects))

For details on format_string, see Format Specifications.

With the single argument format_string, formats objects into the string, then writes the formatted string to $stdout:

printf('%4.4d %10s %2.2f', 24, 24, 24.0)

Output (on $stdout):

0024         24 24.00#

With arguments io and format_string, formats objects into the string, then writes the formatted string to io:

printf($stderr, '%4.4d %10s %2.2f', 24, 24, 24.0)

Output (on $stderr):

0024         24 24.00# => nil

With no arguments, does nothing.

Equivalent to $stdout.print(*objects), this method is the straightforward way to write to $stdout.

Writes the given objects to $stdout; returns nil. Appends the output record separator $OUTPUT_RECORD_SEPARATOR $\), if it is not nil.

With argument objects given, for each object:

• Converts via its method to_s if not a string.

• Writes to stdout.

• If not the last object, writes the output field separator $OUTPUT_FIELD_SEPARATOR ($, if it is not nil.

With default separators:

objects = [0, 0.0, Rational(0, 1), Complex(0, 0), :zero, 'zero']
$OUTPUT_RECORD_SEPARATOR
$OUTPUT_FIELD_SEPARATOR
print(*objects)

Output:

nil
nil
00.00/10+0izerozero

With specified separators:

$OUTPUT_RECORD_SEPARATOR = "\n"
$OUTPUT_FIELD_SEPARATOR = ','
print(*objects)

Output:

0,0.0,0/1,0+0i,zero,zero

With no argument given, writes the content of $_ (which is usually the most recent user input):

gets  # Sets $_ to the most recent user input.
print # Prints $_.

Returns the string resulting from formatting objects into format_string.

For details on format_string, see Format Specifications.

Returns an array containing the items in self:

(0..4).to_a # => [0, 1, 2, 3, 4]

Returns true if coverage stats are currently being collected (after Coverage.start call, but before Coverage.result call)

Returns system configuration variable using confstr().

name should be a constant under Etc which begins with CS_.

The return value is a string or nil. nil means no configuration-defined value. (confstr() returns 0 but errno is not set.)

Etc.confstr(Etc::CS_PATH) #=> "/bin:/usr/bin"

# GNU/Linux
Etc.confstr(Etc::CS_GNU_LIBC_VERSION) #=> "glibc 2.18"
Etc.confstr(Etc::CS_GNU_LIBPTHREAD_VERSION) #=> "NPTL 2.18"

Returns self, for backward compatibility.

Returns current status of GC stress mode.

Updates the GC stress mode.

When stress mode is enabled, the GC is invoked at every GC opportunity: all memory and object allocations.

Enabling stress mode will degrade performance, it is only for debugging.

flag can be true, false, or an integer bit-ORed following flags.

0x01:: no major GC
0x02:: no immediate sweep
0x04:: full mark after malloc/calloc/realloc

Top level install helper method. Allows you to install gems interactively:

% irb
>> Gem.install "minitest"
Fetching: minitest-5.14.0.gem (100%)
=> [#<Gem::Specification:0x1013b4528 @name="minitest", ...>]

Copies a file entry. See install(1).

Arguments src (a single path or an array of paths) and dest (a single path) should be interpretable as paths;

If the entry at dest does not exist, copies from src to dest:

File.read('src0.txt')    # => "aaa\n"
File.exist?('dest0.txt') # => false
FileUtils.install('src0.txt', 'dest0.txt')
File.read('dest0.txt')   # => "aaa\n"

If dest is a file entry, copies from src to dest, overwriting:

File.read('src1.txt')  # => "aaa\n"
File.read('dest1.txt') # => "bbb\n"
FileUtils.install('src1.txt', 'dest1.txt')
File.read('dest1.txt') # => "aaa\n"

If dest is a directory entry, copies from src to dest/src, overwriting if necessary:

File.read('src2.txt')       # => "aaa\n"
File.read('dest2/src2.txt') # => "bbb\n"
FileUtils.install('src2.txt', 'dest2')
File.read('dest2/src2.txt') # => "aaa\n"

If src is an array of paths and dest points to a directory, copies each path path in src to dest/path:

File.file?('src3.txt') # => true
File.file?('src3.dat') # => true
FileUtils.mkdir('dest3')
FileUtils.install(['src3.txt', 'src3.dat'], 'dest3')
File.file?('dest3/src3.txt') # => true
File.file?('dest3/src3.dat') # => true

Keyword arguments:

• group: group - changes the group if not nil, using File.chown.

• mode: permissions - changes the permissions. using File.chmod.

• noop: true - does not copy entries; returns nil.

• owner: owner - changes the owner if not nil, using File.chown.

• preserve: true - preserve timestamps using File.utime.

• verbose: true - prints an equivalent command:

  FileUtils.install('src0.txt', 'dest0.txt', noop: true, verbose: true)
  FileUtils.install('src1.txt', 'dest1.txt', noop: true, verbose: true)
  FileUtils.install('src2.txt', 'dest2', noop: true, verbose: true)
  

  Output:

  install -c src0.txt dest0.txt
  install -c src1.txt dest1.txt
  install -c src2.txt dest2

Related: methods for copying.

Copies a file entry. See install(1).

Arguments src (a single path or an array of paths) and dest (a single path) should be interpretable as paths;

If the entry at dest does not exist, copies from src to dest:

File.read('src0.txt')    # => "aaa\n"
File.exist?('dest0.txt') # => false
FileUtils.install('src0.txt', 'dest0.txt')
File.read('dest0.txt')   # => "aaa\n"

If dest is a file entry, copies from src to dest, overwriting:

File.read('src1.txt')  # => "aaa\n"
File.read('dest1.txt') # => "bbb\n"
FileUtils.install('src1.txt', 'dest1.txt')
File.read('dest1.txt') # => "aaa\n"

If dest is a directory entry, copies from src to dest/src, overwriting if necessary:

File.read('src2.txt')       # => "aaa\n"
File.read('dest2/src2.txt') # => "bbb\n"
FileUtils.install('src2.txt', 'dest2')
File.read('dest2/src2.txt') # => "aaa\n"

If src is an array of paths and dest points to a directory, copies each path path in src to dest/path:

File.file?('src3.txt') # => true
File.file?('src3.dat') # => true
FileUtils.mkdir('dest3')
FileUtils.install(['src3.txt', 'src3.dat'], 'dest3')
File.file?('dest3/src3.txt') # => true
File.file?('dest3/src3.dat') # => true

Keyword arguments:

• group: group - changes the group if not nil, using File.chown.

• mode: permissions - changes the permissions. using File.chmod.

• noop: true - does not copy entries; returns nil.

• owner: owner - changes the owner if not nil, using File.chown.

• preserve: true - preserve timestamps using File.utime.

• verbose: true - prints an equivalent command:

  FileUtils.install('src0.txt', 'dest0.txt', noop: true, verbose: true)
  FileUtils.install('src1.txt', 'dest1.txt', noop: true, verbose: true)
  FileUtils.install('src2.txt', 'dest2', noop: true, verbose: true)
  

  Output:

  install -c src0.txt dest0.txt
  install -c src1.txt dest1.txt
  install -c src2.txt dest2

Related: methods for copying.

Returns the singleton instance.

Returns the scheduling priority for specified process, process group, or user.

Argument kind is one of:

• Process::PRIO_PROCESS: return priority for process.

• Process::PRIO_PGRP: return priority for process group.

• Process::PRIO_USER: return priority for user.

Argument id is the ID for the process, process group, or user; zero specified the current ID for kind.

Examples:

Process.getpriority(Process::PRIO_USER, 0)    # => 19
Process.getpriority(Process::PRIO_PROCESS, 0) # => 19

Not available on all platforms.

See Process.getpriority.

Examples:

Process.setpriority(Process::PRIO_USER, 0, 19)    # => 0
Process.setpriority(Process::PRIO_PROCESS, 0, 19) # => 0
Process.getpriority(Process::PRIO_USER, 0)        # => 19
Process.getpriority(Process::PRIO_PROCESS, 0)     # => 19

Not available on all platforms.

Returns the value of the given instance variable, or nil if the instance variable is not set. The @ part of the variable name should be included for regular instance variables. Throws a NameError exception if the supplied symbol is not valid as an instance variable name. String arguments are converted to symbols.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_get(:@a)    #=> "cat"
fred.instance_variable_get("@b")   #=> 99

Sets the instance variable named by symbol to the given object. This may circumvent the encapsulation intended by the author of the class, so it should be used with care. The variable does not have to exist prior to this call. If the instance variable name is passed as a string, that string is converted to a symbol.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_set(:@a, 'dog')   #=> "dog"
fred.instance_variable_set(:@c, 'cat')   #=> "cat"
fred.inspect                             #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"

Removes the named instance variable from obj, returning that variable’s value. String arguments are converted to symbols.

class Dummy
  attr_reader :var
  def initialize
    @var = 99
  end
  def remove
    remove_instance_variable(:@var)
  end
end
d = Dummy.new
d.var      #=> 99
d.remove   #=> 99
d.var      #=> nil

Defines a public singleton method in the receiver. The method parameter can be a Proc, a Method or an UnboundMethod object. If a block is specified, it is used as the method body. If a block or a method has parameters, they’re used as method parameters.

class A
  class << self
    def class_name
      to_s
    end
  end
end
A.define_singleton_method(:who_am_i) do
  "I am: #{class_name}"
end
A.who_am_i   # ==> "I am: A"

guy = "Bob"
guy.define_singleton_method(:hello) { "#{self}: Hello there!" }
guy.hello    #=>  "Bob: Hello there!"

chris = "Chris"
chris.define_singleton_method(:greet) {|greeting| "#{greeting}, I'm Chris!" }
chris.greet("Hi") #=> "Hi, I'm Chris!"

Returns a list of the private instance methods defined in mod. If the optional parameter is false, the methods of any ancestors are not included.

module Mod
  def method1()  end
  private :method1
  def method2()  end
end
Mod.instance_methods           #=> [:method2]
Mod.private_instance_methods   #=> [:method1]

Returns a list of the undefined instance methods defined in mod. The undefined methods of any ancestors are not included.

Invoked as a callback whenever a singleton method is undefined in the receiver.

module Chatty
  def Chatty.singleton_method_undefined(id)
    puts "Undefining #{id.id2name}"
  end
  def Chatty.one()   end
  class << self
     undef_method(:one)
  end
end

produces:

Undefining one

Verify internal consistency.

This method is implementation specific. Now this method checks generational consistency if RGenGC is supported.

Default options for gem commands for Ruby packagers.

The options here should be structured as an array of string “gem” command names as keys and a string of the default options as values.

Example:

def self.operating_system_defaults

{
    'install' => '--no-rdoc --no-ri --env-shebang',
    'update' => '--no-rdoc --no-ri --env-shebang'
}

end