Ruby - Predefined Constants


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The following table lists all the Ruby's Predefined Constants −

NOTE − TRUE, FALSE, and NIL are backward-compatible. It's preferable to use true, false, and nil.

Sr.No. Constant Name & Description
1 TRUE

Synonym for true.

2 FALSE

Synonym for false.

3 NIL

Synonym for nil.

4 ARGF

An object providing access to virtual concatenation of files passed as command-line arguments or standard input if there are no command-line arguments. A synonym for $<.

5 ARGV

An array containing the command-line arguments passed to the program. A synonym for $*.

6 DATA

An input stream for reading the lines of code following the __END__ directive. Not defined if __END__ isn't present in code.

7 ENV

A hash-like object containing the program's environment variables. ENV can be handled as a hash.

8 RUBY_PLATFORM

A string indicating the platform of the Ruby interpreter.

9 RUBY_RELEASE_DATE

A string indicating the release date of the Ruby interpreter

10 RUBY_VERSION

A string indicating the version of the Ruby interpreter.

11 STDERR

Standard error output stream. Default value of $stderr.

12 STDIN

Standard input stream. Default value of $stdin.

13 STDOUT

Standard output stream. Default value of $stdout.

14 TOPLEVEL_BINDING

A binding object at Ruby's top level.



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