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File extension is in extensions list: Difference between revisions
File extension is in extensions list (view source)
Revision as of 17:17, 12 August 2014
, 9 years ago+Java, probably complex
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Exts isExt TestFiles
1 1 0 1 0 0</lang>
=={{header|Java}}==
{{works with|Java|1.5+}}
<lang java5>import java.util.Arrays;
import java.util.Comparator;
public class FileExt{
public static void main(String[] args){
String[] tests = {"text.txt", "text.TXT", "test.tar.gz", "test/test2.exe", "test\\test2.exe", "test", "a/b/c\\d/foo"};
String[] exts = {".txt",".gz","",".bat"};
System.out.println("Extensions: " + Arrays.toString(exts) + "\n");
for(String test:tests){
System.out.println(test +": " + extIsIn(test, exts));
}
}
public static boolean extIsIn(String test, String... exts){
int lastSlash = Math.max(test.lastIndexOf('/'), test.lastIndexOf('\\')); //whichever one they decide to use today
String filename = test.substring(lastSlash + 1);//+1 to get rid of the slash or move to index 0 if there's no slash
//end of the name if no dot, last dot index otherwise
int lastDot = filename.lastIndexOf('.') == -1 ? filename.length() : filename.lastIndexOf('.');
String ext = filename.substring(lastDot);//everything at the last dot and after is the extension
Arrays.sort(exts);//sort for the binary search
return Arrays.binarySearch(exts, ext, new Comparator<String>() { //just use the built-in binary search method
@Override //it will let us specify a Comparator and it's fast enough
public int compare(String o1, String o2) {
return o1.compareToIgnoreCase(o2);
}
}) >= 0;//binarySearch returns negative numbers when it's not found
}
}
</lang>
{{out}}
<pre>Extensions: [.txt, .gz, , .bat]
text.txt: true
text.TXT: true
test.tar.gz: true
test/test2.exe: false
test\test2.exe: false
test: true
a/b/c\d/foo: true</pre>
=={{header|Perl 6}}==
<lang perl6>my @ext = < .c .o >;
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