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Reading through a list of Rails questions, I'm having trouble finding what the %i does in relation to a symbol array. Does this mean anything to anyone?

Mark
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2 Answers2

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Lowercase %i stands for

Non-interpolated Array of symbols, separated by whitespace (after Ruby 2.0)

In addition, uppercase %I means

Interpolated Array of symbols, separated by whitespace (after Ruby 2.0)

Example of difference regarding interpolation:

2.4.2 :001 > a = 1
2.4.2 :002 > %i{one two #{a}+three} # Interpolation is ignored
 => [:one, :two, :"\#{a}+three"]
2.4.2 :003 > %I{one two #{a}+three} # Interpolation works
 => [:one, :two, :"1+three"]

Have a look at here for further information.

Andres
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I'm having trouble finding what the %i does in relation to a symbol array.

It is an array literal for an array of symbols. It does the same thing in relation to symbol arrays as ' does to strings.

Jörg W Mittag
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  • Some useful examples here: https://simpleror.wordpress.com/2009/03/15/q-q-w-w-x-r-s/ – Mark Oct 03 '16 at 17:00
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    So %i and %I are almost the same thing as %w and %W. Difference between "interpolated" and 'non-interpolated' is not obvious either, but it's the difference between double-quotes (which interpolate \n and #{...} items) and single-quotes (which do not) – Mark Oct 03 '16 at 17:06