Comments on: Help with regex exp. for Yahoo Pipes

Question: Help with regex exp. for Yahoo Pipes

jingo74 — Fri, 03 Apr 2009 16:40:51 -0800

I'm a librarian who uses Yahoo Pipes in combination with RSS feeds for new books from Amazon to order books. The title tags in each individual item begin as in this example: "#1: A. Lincoln: A Biography". I would like to add a regex expression that will strip out the ranking (#1: or #10:) out of the title so that I can sort the book titles. What I want to remove is the # sign, the ranking number (one or two digit number), and the colon. Any help would be appreciated.

By: Ginkgo

Ginkgo — Fri, 03 Apr 2009 16:55:58 -0800

#\d+: would find that pattern if that helps...

By: pb

pb — Fri, 03 Apr 2009 16:57:33 -0800

You might try adding a regex filter where you choose the item title and replace ^#\d{1,2}: with nothing. That should match the number sign followed by one or two digits and a colon at the beginning of the title.

By: Mike1024

Mike1024 — Fri, 03 Apr 2009 17:42:04 -0800

I don't know Yahoo Pipes, but I can tell you how I would do that with Perl's regular expressions, and I'd do it like this:

$a = "#1: A. Lincoln: A Biography";
$a =~ s/^#\d+:\s*// ;
print "$a \n";

Which says (in short) find the pattern ^#\d+:\s* (i.e. start of line, # sign, 1 or more digits, colon, zero or more spaces) and replace it with nothing.

Unfortunately I don't have a yahoo account, and I can't find much documentation for yahoo pipes regular expressions.

By: dreadpiratesully

dreadpiratesully — Fri, 03 Apr 2009 20:09:06 -0800

If you can't do replacement but grouping works (I, too, am ignorant of Pipes), /^#\d+:\s*(.*)/ should give you everything after the colon and adjacent whitespace (the title, in your example) as $1 or the Yahoo equivalent.