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<title>Ruby FAQ:
Undocumented Features
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<h2><a name="s9">9.
Undocumented Features
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<h2><a name="ss9.1">9.1
What does <code>a ? b : c</code> mean?
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It means <code>if a then b else c end</code>.
<h2><a name="ss9.2">9.2
How can I count the number of lines in a file?
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Assuming that the file ends in a linefeed, following code may give the
fastest result.
<code>open("file").read.count("\n")</code>
<h2><a name="ss9.3">9.3
What do <code>begin</code> and <code>end</code> of MatchingData return?
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They act with $~, and return the start index and the end index of
matched data $0, $1... in the original string. See an example
in <a href="rubyfaq-7.html#tab">tab expansion</a>.
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