Using RE to extract pattern from custom column into another custom column

[activedirectory]

This is a really basic question so thanks for being patient.

I have a custom column from the Overdrive plugin (thanks jhowell!) that shows the waiting time for my holds: for example a row would look like:

05H@library1, 08@library2, 09@library3

I am trying to create another custom that just shows that I have a hold on this book e.g. H@library1 (the re pattern would be like like H@[a-z1-9]+)

I've used regular expression but I don't know how to reference the custom columns... and I was a bit confused by the help files.

[davidfor]

Each column has a lookup name. For a custom column, it will start with a "#". You don't enter this when creating a custom column, but, all references to it need it. Once you have the lookup name correct, it is used in the same way as an inbuilt column.

For example, if you created the column as "od_holds", then simplest template with it would be:

{#od_holds}