Ruby - Special Variables and Pseudo-Variables

Special Variables and Pseudo-Variables - Ruby module R110

Every operation has a result. Easy - store it to a varibale. But operations have side effects too that you can read from special variables. And the very act of running your script provides a wide variety of extra information that you may want to use ... and is there, if you know where, for the asking.

This topic is presented on public course Ruby Programming

Examples from our training material

cc	begin block
gloop1	Topicalisation - before
gloop2	Topicalisation - after
pgv.rb	predefined global variables and resources
ruby_awk.rb	implicit loop around code - awk mode
topic.rb	Topicalisation - the use of $_
vvx	variable types

Background information

Some modules are available for download as a sample of our material or under an Open Training Notes License for free download from http://www.training-notes.co.uk.

Topics covered in this module

ARGV, $0 and friends - the command line.
Other special variables from $: through $$ to $<.
Environment variables.
Pseudo-variables.
Reserved words in Ruby.

Complete learning

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