The Pickled Piper

By which I mean lumping selected elements from all the items in a feed into a single item.

A word of warning first. This technique involves using a string of numbers in the form “0,1,2,3”, where the highest number will be the maximum (-1) number of items  possible in the feed. If you’re looking to lump together 50 items and aren’t willing to build the relevant string then this is not for you.

Let’s have a look at my pipe that does this.

Here we have a URL Input module, an Item Builder a Fetch Data module in a Loop and a Split. The main thing to notice here is that in the normal run of things I could just have used a URL Input module and a Fetch Data, but what I want is for my items to appear as a sub-element array.

If you want to have more than one element in the output, or you want to format the elements, then use a sub-pipe instead of my Fetch Data module to do that work.

Now let’s see what’s happening in the right-hand path of the Split.

We need the Sub-element so that we can then use the Count to output the number of items in the feed. If we have 2 items then the String Regex converts that number to “,2.*”. This is where that string of numbers I mentioned earlier comes in.

The first rule in this String Regex removes “,2” and everything after that, and the second rule wraps what is left inside “${stuff.” and “.title}”. Finally the String Replace replaces each of the commas with the string on the right. The outcome of all this is that we end up with a string like “${stuff.0.title}<br>${stuff.1.title}”. In case you weren’t aware, in the Regex module we can refer to elements of an item using $(element path excluding item.}. And now we can plug this into the Regex module in the left-hand path of the Split.

The grand result of this is that I can show off the first 2 titles of my blog posts.

I think that could be 3 titles fairly soon.

Tags: Yahoo Pipes

This entry was posted on May 20, 2009 at 3:57 pm and is filed under Pipes. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.