File extension is in extensions list: Difference between revisions
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isExt :: String -> [String] -> Bool |
isExt :: String -> [String] -> Bool |
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isExt filename extensions = any (`elem` (tails . toLower $ filename)) $ map toLower extensions |
isExt filename extensions = any (`elem` (tails . toLower $ filename)) $ map toLower extensions |
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</lang> |
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The code defining isExt could be done point free: |
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<lang Haskell> |
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isExt filename = any (`elem` (tails . toLower $ filename)) . map toLower |
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</lang> |
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Overcoming the one-liner urge on behalf of being more comprehensible would give: |
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<lang Haskell> |
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isExt filename extensions = any (`elem` allTails) lowerExtensions |
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where allTails = tails . toLower $ filename |
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lowerExtensions = map toLower extensions |
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</lang> |
</lang> |
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Revision as of 17:09, 11 August 2014
You are encouraged to solve this task according to the task description, using any language you may know.
Given a file name and a list of extensions (including the dot), tell whether the file's extension is in the extensions list. The check should be case insensitive. The file might not have an extension.
Haskell
<lang Haskell> import Data.List import qualified Data.Char as Ch
toLower :: String -> String toLower = map Ch.toLower
isExt :: String -> [String] -> Bool isExt filename extensions = any (`elem` (tails . toLower $ filename)) $ map toLower extensions </lang>
The code defining isExt could be done point free: <lang Haskell> isExt filename = any (`elem` (tails . toLower $ filename)) . map toLower </lang>
Overcoming the one-liner urge on behalf of being more comprehensible would give: <lang Haskell> isExt filename extensions = any (`elem` allTails) lowerExtensions where allTails = tails . toLower $ filename lowerExtensions = map toLower extensions </lang>
Python
<lang Python> import os
def isExt(filename, extensions):
return os.path.splitext(filename.lower())[-1] in [e.lower() for e in extensions]
</lang>
Scala
<lang Scala> def isExt(fileName: String, extensions: List[String]): Boolean = {
extensions.map { _.toLowerCase }.exists { fileName.toLowerCase endsWith _ }
} </lang>