Ruby Class and Library Reference

This page lists the built-in Ruby classes and modules, and the methods they contain. Click on a class, module, or method name for a detailed description.

classes

Array	[ ] new & * + - << <=> == === [ ] [ ]= \| assoc at clear collect collect! compact compact! concat delete delete_at delete_if each each_index empty? eql? fill first flatten flatten! include? index indexes indices join last length map! nitems pack pop push rassoc reject! replace reverse reverse! reverse_each rindex shift size slice slice! sort sort! to_a to_ary to_s uniq uniq! unshift
Bignum	Arithmetic operations Bit operations <=> [ ] size to_f to_i to_s
Binding
Class	inherited new new superclass
Continuation	call
Dir	[ ] chdir chroot delete entries foreach getwd glob mkdir new open pwd rmdir unlink close each read rewind seek tell
Exception	exception backtrace exception message set_backtrace
FalseClass	& ^ \|
File	atime basename chmod chown ctime delete dirname expand_path ftype join link lstat mtime new open readlink rename size split stat symlink truncate umask unlink utime atime chmod chown ctime flock lstat mtime path truncate
File::Stat	<=> atime blksize blockdev? blocks chardev? ctime dev directory? executable? executable_real? file? ftype gid grpowned? ino mode mtime nlink owned? pipe? rdev readable? readable_real? setgid? setuid? size size? socket? sticky? symlink? uid writable? writable_real? zero?
Fixnum	Arithmetic operations Bit operations <=> [ ] id2name size to_f to_i to_s
Float	Arithmetic operations <=> ceil finite? floor infinite? nan? round to_f to_i to_s
Hash	[ ] new == [ ] [ ]= clear default default= delete delete_if each each_key each_pair each_value empty? fetch has_key? has_value? include? index indexes indices invert key? keys length member? rehash reject reject! replace shift size sort store to_a to_s update value? values
Integer	chr downto integer? next step succ times upto
IO	foreach new pipe popen readlines select << binmode clone close close_read close_write closed? each each_byte each_line eof eof? fcntl fileno flush getc gets ioctl isatty lineno lineno= pid pos pos= print printf putc puts read readchar readline readlines reopen rewind seek stat sync sync= sysread syswrite tell to_i to_io tty? ungetc write
MatchData	[ ] begin end length offset post_match pre_match size string to_a to_s
Method	[ ] arity call to_proc
Module	constants nesting new <, <=, >, >= <=> === ancestors class_eval class_variables clone const_defined? const_get const_set constants included_modules instance_methods method_defined? module_eval name private_class_method private_instance_methods protected_instance_methods public_class_method public_instance_methods alias_method append_features attr attr_accessor attr_reader attr_writer extend_object include method_added module_function private protected public remove_const remove_method undef_method
NilClass	& ^ \| nil? to_a to_i to_s
Numeric	+@ -@ abs coerce divmod eql? integer? modulo nonzero? remainder zero?
Object	== === =~ __id__ __send__ class clone display dup eql? equal? extend freeze frozen? hash id inspect instance_eval instance_of? instance_variables is_a? kind_of? method method_missing methods nil? private_methods protected_methods public_methods respond_to? send singleton_methods taint tainted? to_a to_s type untaint
Proc	new [ ] arity call
Range	new === begin each end exclude_end? first last length size
Regexp	compile escape last_match new quote == === =~ ~ casefold? kcode match source
String	new % * + << <=> == === =~ [ ] [ ]= ~ capitalize capitalize! center chomp chomp! chop chop! concat count crypt delete delete! downcase downcase! dump each each_byte each_line empty? gsub gsub! hash hex include? index intern length ljust next next! oct replace reverse reverse! rindex rjust scan size slice slice! split squeeze squeeze! strip strip! sub sub! succ succ! sum swapcase swapcase! to_f to_i to_s to_str tr tr! tr_s tr_s! unpack upcase upcase! upto
Struct	new new members == [ ] [ ]= each length members size to_a values
Struct::Tms
Symbol	id2name inspect to_i to_s
Thread	abort_on_exception abort_on_exception= critical critical= current exit fork kill list main new pass start stop [ ] [ ]= abort_on_exception abort_on_exception= alive? exit join key? kill priority priority= raise run safe_level status stop? value wakeup
ThreadGroup	new add list
Time	at gm local mktime new now times utc + - <=> asctime ctime day gmt? gmtime hour isdst localtime mday min mon month sec strftime to_a to_f to_i to_s tv_sec tv_usec usec utc utc? wday yday year zone
TrueClass	& ^ \|


modules

Comparable	Comparisons between?
Enumerable	collect detect each_with_index entries find find_all grep include? map max member? min reject select sort to_a
Errno
FileTest
GC	disable enable start garbage_collect
Kernel	Array Float Integer String ` (backquote) abort at_exit autoload binding block_given? callcc caller catch chomp chomp! chop chop! eval exec exit exit! fail fork format gets global_variables gsub gsub! iterator? lambda load local_variables loop open p print printf proc putc puts raise rand readline readlines require scan select set_trace_func singleton_method_added sleep split sprintf srand sub sub! syscall system test throw trace_var trap untrace_var
Marshal	dump load restore
Math	atan2 cos exp frexp ldexp log log10 sin sqrt tan
ObjectSpace	_id2ref define_finalizer each_object garbage_collect undefine_finalizer
Process	egid egid= euid euid= exit! fork getpgid getpgrp getpriority gid gid= kill pid ppid setpgid setpgrp setpriority setsid uid uid= wait wait2 waitpid waitpid2