Re: regex help

Don't see how your regex could do what you say. Your "^(\d)$" is looking for a SINGLE digit between start of record/string, "^," and the end of same, "$."

What follows sorta' does what you're talking about altho in the regex you'll need to do "(012346" rather than "(\d{6}" or some variant of (any digit except 5,7, 8 or 9) or similarly clunky approaches to deal with the exact string

and, is this homework? If so, it's a good idea to mention ('fess up) that fact, so monks can teach without actually DOING the homework.


#!C:/perl/bin -w
use strict;

use vars qw ($input @input @img $img);

@input = <DATA> ;

foreach $input (@input) {
    if ( $input =~         # Caret in next line: Start at begining of 
+string/record/whatever
            /^(\d{6}            # sTART CAPTURE, with any digit, [0-9]
+, exactly six times.
            (-                    # optionally (trailing "?") in a NON
+-capture-group: a dash followed by a
            \w{3})?            # word char, exactly 3 times; end group
+ing parens
            \.jpg$            # literal period followed by "jpg" endin
+g the string
            )                    # end capture
            /ix ) {             #case insensitive (to catch -all and -
+EXP); extended form

    push(@img, $input);
    }
}
print "\n\t+++++\n";
print @img;
print "\n\tdone\n";
exit;

__DATA__
012346.jpg
012346-all.jpg
012346-EXP.jpg
012346-exp.jpg
012346-ALL.jpg
012345.jpg
12345.jpg
01234.jpeg
0123345+ALL.jpg
0123345-exp.jpg
0123345-ALL.jpg
not_jpg.last
[download]

note that the last 6 items in data do NOT match the regex.

Comment on Re: regex help Download Code

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Re^2: regex help by calypso (Initiate) on Nov 17, 2004 at 17:36 UTC
I sure am a perl novice. Its not homework, its a little project script I am working on. sorry, I mistyped that regex, this "$imgNumber =~/^(\d{6})/" not "^(\d)$" is what gave me 012346.jpg. I took care of the .jpg by just recursively printing "$imgNumber.jpg"; and it worked. I was just confused as to how to catch the "-ALL" or "-EXP" "-SAMPLE" part of it with regular expressions. And if possible, I sure would like some teaching on regex. i googled some tut but was still quite confused. Thanks for the help.	[reply]
Re^3: regex help by ww (Archbishop) on Nov 17, 2004 at 18:15 UTC
Calypso -- I'm not more'n a step or two ahead of you so forgive any of this which you know and practice already: PREVIEW, PREVIEW, PREVIEW! CUT'n'PASTE FROM TESTED CODE (it doesn't have to work if it's an illustration of a failure, but it does have to be -- verbatim -- what you intended to ask about. Specifically re regexen, since you've reached the point you describe, your next step (IMO) should be to read up on /x, extended format. It really is worth the effort because it makes the regex so readable. Think you'll find good info in perlretut, for which, search or supersearch here. Also will try (when next at home computer) to find some links to some of the better on-line tutorials I stumbled upon. And BTW, I have been chastised for using telegraphese (which bears some resemblence to sms texting as practiced by the teen crowd; which association may or may not have been what most annoyed the critics). Nonetheless, they offered other observations which were thoughtful and useful. I, for one, don't wish to impede my communication with them by using forms of which they disapprove, nor by being ambiguous/unclear or inaccurate. So I offer you a related (that is, I hope you think it's related) thought: Format your post in a manner that approximates standard syntax and grammar. Structure your notes with paragraphs and typographic conventions that make your message easy to read and follow.... and, above all, make sure you've thought thru, clearly and carefully, just what it is you wish to say. A few of us are so elderly or dinosaur-ish as to believe it rude to utter notes shot through with typos....	[reply]