Extract file extension: Difference between revisions
Rename Perl 6 -> Raku, alphabetize, minor clean-up
Thundergnat (talk | contribs) (Rename Perl 6 -> Raku, alphabetize, minor clean-up) |
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return exitcode;
}</lang>
=={{header|C sharp|C#}}==
<lang [[C sharp|C#]]>public static string FindExtension(string filename) {
int indexOfDot = filename.Length;
for (int i = filename.Length - 1; i >= 0; i--) {
char c = filename[i];
if (c == '.') {
indexOfDot = i;
break;
}
if (c >= '0' && c <= '9') continue;
if (c >= 'A' && c <= 'Z') continue;
if (c >= 'a' && c <= 'z') continue;
break;
}
//The dot must be followed by at least one other character,
//so if the last character is a dot, return the empty string
return indexOfDot + 1 == filename.Length ? "" : filename.Substring(indexOfDot);
}</lang>
'''Using regular expressions (C# 6)'''
<lang [[C sharp|C#]]>public static string FindExtension(string filename) => Regex.Match(filename, @"\.[A-Za-z0-9]+$").Value;</lang>
=={{header|C++}}==
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thisismine. has extension : !
</pre>
=={{header|Common Lisp}}==
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=>
"txt"</lang>
=={{header|D}}==
Line 542 ⟶ 525:
/etc/pam.d/login ->
</pre>
=={{header|Emacs Lisp}}==
<lang Lisp>(file-name-extension "foo.txt")
=>
"txt"</lang>
No extension is distinguished from empty extension but an <code>(or ... "")</code> can give <code>""</code> for both if desired
<lang Lisp>(file-name-extension "foo.") => ""
(file-name-extension "foo") => nil</lang>
An Emacs backup <code>~</code> or <code>.~NUM~</code> are not part of the extension, but otherwise any characters are allowed.
<lang Lisp>(file-name-extension "foo.txt~") => "txt"
(file-name-extension "foo.txt.~1.234~") => "txt"</lang>
=={{header|Factor}}==
Line 1,475 ⟶ 1,474:
document.txt_backup ''
/etc/pam.d/login ''
</pre>
Line 1,751 ⟶ 1,712:
document.txt_backup |
/etc/pam.d/login |
</pre>
=={{header|Raku}}==
(formerly Perl 6)
The built-in <code>IO::Path</code> class has an <code>.extension</code> method:
<lang perl6>say $path.IO.extension;</lang>
Contrary to this task's specification, it
* doesn't include the dot in the output
* doesn't restrict the extension to letters and numbers.
Here's a custom implementation which does satisfy the task requirements:
<lang perl6>sub extension (Str $path --> Str) {
$path.match(/:i ['.' <[a..z0..9]>+]? $ /).Str
}
# Testing:
printf "%-35s %-11s %-12s\n", $_, extension($_).perl, $_.IO.extension.perl
for <
http://example.com/download.tar.gz
CharacterModel.3DS
.desktop
document
document.txt_backup
/etc/pam.d/login
>;</lang>
{{out}}
<pre>
http://example.com/download.tar.gz ".gz" "gz"
CharacterModel.3DS ".3DS" "3DS"
.desktop ".desktop" "desktop"
document "" ""
document.txt_backup "" "txt_backup"
/etc/pam.d/login "" ""
</pre>
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