Extract file extension: Difference between revisions
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(→{{header|Perl 6}}: replace the solution with a simpler one, and mention the built-in ".extension" method) |
(→Task: some more re-wording, and explicitly restrict to ASCII letters and numbers) |
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{{draft task}} |
{{draft task}} |
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[[wp:Filename extension|Filename extensions]] are a rudimentary but commonly used way of identifying files types. |
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{{task heading}} |
{{task heading}} |
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Write a function or program that |
Write a function or program that |
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* takes one string argument representing the path/URL to a file |
* takes one string argument representing the path/URL to a file |
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* returns the |
* returns the filename extension according to the below specification, or an empty string if the filename has no extension. |
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If your programming language (or standard library) has built-in functionality for extracting a filename extension, show how it would be used, and clearly state how its behavior differs from this specification. |
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For the purposes of this task, a filename extension |
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* occurs at the very end of the filename |
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* An extension appears after the last period in the file's name, and consists of one or more letters or numbers. |
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* consists of a period, followed by one or more ASCII letters or numbers |
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* The file name is separated from preceding directory parts, if any, by a forward slash. |
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{{task heading|Test cases}} |
{{task heading|Test cases}} |
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| <code>file.odd_one</code> |
| <code>file.odd_one</code> |
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| <code></code> |
| <code></code> |
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| ''empty string, |
| ''empty string, because <code>_</code> is not a letter or number'' |
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