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    <p>Voila!, one benchmark:</p> <pre><code>require 'benchmark' n = 1_000_000 Benchmark.bm(11) do |b| b.report('%w') { n.times { %w[a b c d e f g h i j k l m n o p q r s t u v w x y z] } } b.report('explicit') { n.times { ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'] } } b.report('numerics') { n.times { [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26] } } end user system total real %w 2.590000 0.000000 2.590000 ( 2.591225) explicit 2.590000 0.000000 2.590000 ( 2.584781) numerics 0.300000 0.000000 0.300000 ( 0.309161) user system total real %w 2.590000 0.000000 2.590000 ( 2.591516) explicit 2.590000 0.000000 2.590000 ( 2.584155) numerics 0.300000 0.000000 0.300000 ( 0.308896) user system total real %w 2.590000 0.000000 2.590000 ( 2.592848) explicit 2.590000 0.000000 2.590000 ( 2.585558) numerics 0.300000 0.000000 0.300000 ( 0.308570) </code></pre> <p>I added the "numerics" array test because I suspected that <code>%w</code> is faster than using explicit strings due to testing for stringiness. <code>%w</code> doesn't need to do that, because it assumes everything is a string. After running it three times it's a wash as far as dealing with strings. Numbers rule, strings drool, and all that.</p> <hr> <p>The previous benchmarks were run using Ruby 1.9.3-p286 on my system at work. I tested again using my old MacBook Pro at home, using Ruby 1.8.7-p358, so the following numbers are slower due to the differences in the hosting hardware, plus running an older Ruby:</p> <pre><code> user system total real %w 3.070000 0.000000 3.070000 ( 3.080983) explicit 3.100000 0.000000 3.100000 ( 3.093083) numerics 0.950000 0.040000 0.990000 ( 0.990535) user system total real %w 3.080000 0.010000 3.090000 ( 3.076787) explicit 3.090000 0.000000 3.090000 ( 3.089246) numerics 0.950000 0.030000 0.980000 ( 0.989579) user system total real %w 3.080000 0.000000 3.080000 ( 3.073877) explicit 3.090000 0.000000 3.090000 ( 3.091576) numerics 0.950000 0.030000 0.980000 ( 0.989132) </code></pre> <p>On 1.8.7, <code>%w</code> was a tiny bit faster consistently, which probably gave rise to the speed-rumors.</p>
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    1. POPrefer %w(...) to a literal array?
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    1. USthe Tin Man
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    1. CO+1: Nice. Learned at least 3 things here.
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      1. USJohn Dibling
    2. COBoth are *exactly the same thing*. If there even *was* any performance difference, it could *only* be during *parsing*. There *cannot* possibly be any *runtime* performance difference, because both are the *exact same thing*. Since the entire file is parsed *before* the benchmark is even started, the entire benchmark is meaningless. You would need to use `eval` or `load` or something like that to delay the parsing until after the benchmark has started.
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      1. USJörg W Mittag
    3. CO@JörgWMittag You assert they are the exact same thing; but that's only true with a _sufficiently smart compiler_. %w{...} is always an array of literals, while `[...]` can be an array of literals or an array of expressions or a mix. The compiler can analyze the array after parsing to understand it's an array of literals and therefore fully construct it at code generation time, but that's not a completely trivial optimization one should always assume you get without documentation, testing or code inspection.
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