Perl: find the last occurrence of the char "\"

Question

I want to strip the path from a file string like this:

Root\ToOrganization\Service_b37189b3-8505-4395_Out_BackOffice.xml

I am trying to find the index of the last occurrence of "\" so I can use substring up to there.

but I can't use the char "\" in the search. I am using "\" instead, but its not working...

my code i am trying :

$file = "Root\ToOrganization\Service_b37189b3-8505-4395_Out_BackOffice.xml";
$tmp = rindex($file, "\\");
print $tmp;

the OUTPUT I'm getting:

-1

What can I do?

Hint: You have a double backslash in your `rindex` call, but only single backslashes in your path. Why? — melpomene, Oct 11 '15 at 11:58
@melpomene , the line will come by reading a text file, and that is the format im getting from the test file lines... — David Gidony, Oct 11 '15 at 12:06
No, it's not. Your code would have worked fine for lines coming from a text file. — melpomene, Oct 11 '15 at 12:08

melpomene · Accepted Answer · 2015-10-11T12:17:17.587

The main problem is your use of invalid escapes:

use warnings;
print "Root\ToOrganization\Service_b37189b3-8505-4395_Out_BackOffice.xml";

Unrecognized escape \T passed through at ... line 2.
Unrecognized escape \S passed through at ... line 2.
RootToOrganizationService_b37189b3-8505-4395_Out_BackOffice.xml

So your $file variable doesn't contain what you think it does.

Your rindex call itself is fine, but you can simply do this (assuming you are on a Windows system):

use strict;
use warnings;
use File::Basename;

my $path = "Root\\ToOrganization\\Service_b37189b3-8505-4395_Out_BackOffice.xml";
my $dir = dirname($path);
print "dir = $dir\n";

Or (this should work on any system):

use strict;
use warnings;
use File::Spec::Win32;

my $path = "Root\\ToOrganization\\Service_b37189b3-8505-4395_Out_BackOffice.xml";
my $dir = (File::Spec::Win32->splitpath($path))[1];
print "dir = $dir\n";

Note that if this is actually a real windows path, the code above will strip the drive letter (it's the first element of the list returned by splitpath).

this is a great answer, the only problem is that your code return the filename, and i need the directory structure witout the file name :) — David Gidony, Oct 11 '15 at 12:11

score 0 · Answer 2 · answered Oct 12 '15 at 08:20

double-quotes interpolate escapes \T and \S, so you should use single quotes ' or q// to test. Anyway, reading from file (for example, with <>) will work for you without any changes in reindex-related code, i.e. this works fine:

warn rindex ($_, "\\") while (<>);

Perl: find the last occurrence of the char "\"

2 Answers2