liveBook · Manning

%i array constructor

As explained in The Well-Grounded Rubyist, Fourth Edition

The %i array constructor is Ruby syntax that creates an array of symbols from whitespace-separated content, with %I enabling double-quoted interpolation rules.

Use %i with a delimiter to create an array of symbols from whitespace-separated content: %i(a b c) produces [:a, :b, :c]. section 9.2.1

Contrast the related forms:

  • %i creates symbols without interpolation. section 9.2.1
  • %I enables double-quoted interpolation rules, as in %I("#{d}"). section 9.2.1
  • %w and %W provide corresponding whitespace-separated string arrays. section 9.2.1
>> %i(a b c)
=> [:a, :b, :c]
>> d = "David"
=> "David"
>> %I("#{d}")
=> [:"\"David\""]

Compare ordinary symbol construction with interpolated %I syntax and inspect the resulting arrays. section 9.2.1

How The Well-Grounded Rubyist, Fourth Edition covers it

How deep it goes
Defines %i and contrasts %I interpolation, but does not detail delimiter escaping or broader symbol semantics.
Examples
Demonstrates %i(a b c), interpolated %I content, and corresponding %w and %W forms.
What you can do after
Build symbol arrays with %i and choose %I when interpolation rules are required.
How it connects
Connects symbol arrays with array constructors, string arrays, and string interpolation.
Cover of The Well-Grounded Rubyist, Fourth Edition
liveBookmanning.com
Read The Well-Grounded Rubyist, Fourth Edition on liveBook Get the book at manning.com

This explainer was generated by Manning's knowledge graph from the text of The Well-Grounded Rubyist, Fourth Edition. The section links point to the parts of the book it draws on.