Filtering the list – ”not equal to” operator for selection list options

[Johan Vallon-Christersson]

When filtering an item list some columns that can only take a few distinct values use a selection list. The selection list is very simple to use; by simply selecting the alternative that you want to filter on, only matching items are displayed. You can also show all by selecting the ‘blank’ alternative in the list.

A common scenario involves wanting to display items that do not match one of the alternatives in the selection list. For example, for a list of samples annotated with typeA, typeB, typeC, or no_type_available you might want to display sample with an available type (A-C) and exclude the samples for which no type is available (no_type_available).

It would then be useful to be able to have the option to exclude items based on a value in the selection list.

One possible interface for this added functionality could be that alternatives for exclude can be given in the list, e.g., for the example above the alternatives in the selection list would include:

‘blank’ (the available option to show all)
typeA
typeB
typeC
no_type_available
<>typeA
<>typeB
<>typeC
<>no_type_available

[Nicklas Nordborg]

Hmm... would it be possible to convert the list to something that allows multiple selections...

In a sense this is easy to do by adding a 'multiple' attribute to the <select> tag, but this interface is not very good. Maybe we should create our own type of control which is some kind of dropdown with checkboxes.

In addition alternatives to display or exclude items with a null value would be useful.
null value
<>null value

The null/not null support is not related to this and is moved to a separate ticket #964.