Slice
#####

Return a slice of a list (array).

This is useful if we wish to extract only a certain number of elements from an
array, for example splitting a large list into two lists.

Arguments
=========

The filter has two arguments **start** and **end**.

These tell the filter which elements to return from the list.

Both arguments can be either a number (positive integer) or a keyword.

.. note::

   Mixing numbers and keywords is not allowed

   i.e. either both arguments are numbers or both arguments are keywords

The keywords are:

- "start" - the first element
- "middle" - the element that is in the middle of the list
- "end" - the last element in the list

Example arguments
-----------------

+-----------+----------+----------------------------------------------------------------+
| **start** | **end**  | **Comment**                                                    |
+-----------+----------+----------------------------------------------------------------+
| "start"   | "end"    | returns the whole list                                         |
+-----------+----------+----------------------------------------------------------------+
| "start"   | "middle" | returns the first half of the list                             |
+-----------+----------+----------------------------------------------------------------+
| "middle"  | "end"    | returns the second half of the list                            |
+-----------+----------+----------------------------------------------------------------+
| 0         | 1        | returns the first element                                      |
+-----------+----------+----------------------------------------------------------------+
| 1         | 3        | returns the second element                                     |
+-----------+----------+----------------------------------------------------------------+
| 0         | 4        | returns everything from the first **UP TO** the fourth element |
+-----------+----------+----------------------------------------------------------------+

Example usage
=============

**Template**

.. code-block:: text

   {# damage | slide:"start":"middle" } {component}, {/}


**Output**

::

   NSF Bumper, Front Bumper, OFF Bumper, Grill


Using slice to save vertical space
==================================

Sometime we show a list of items as two columns.

Each column displaying a different value from the item e.g. label and agreed.

When we have a very long list, this pattern will waste a lot of space.

To work around this we want the whole list split into two columns.

For example we want to display a table like this

+-----------+------------+
| **Label** | **Agreed** |
+-----------+------------+
| Label 00  | £100.00    |
+-----------+------------+
| Label 01  | £100.00    |
+-----------+------------+
| Label 02  | £100.00    |
+-----------+------------+
| Label 03  | £100.00    |
+-----------+------------+
| Label 04  | £100.00    |
+-----------+------------+
| Label 05  | £100.00    |
+-----------+------------+
| Label 06  | £100.00    |
+-----------+------------+
| Label 07  | £100.00    |
+-----------+------------+
| Label 08  | £100.00    |
+-----------+------------+
| Label 09  | £100.00    |
+-----------+------------+
| Label 10  | £100.00    |
+-----------+------------+

As two columns:

+-----------+------------+-----------+------------+
| **Label** | **Agreed** | **Label** | **Agreed** |
+-----------+------------+-----------+------------+
| Label 00  | £100.00    | Label 05  | £100.00    |
+-----------+------------+-----------+------------+
| Label 01  | £100.00    | Label 06  | £100.00    |
+-----------+------------+-----------+------------+
| Label 02  | £100.00    | Label 07  | £100.00    |
+-----------+------------+-----------+------------+
| Label 03  | £100.00    | Label 08  | £100.00    |
+-----------+------------+-----------+------------+
| Label 04  | £100.00    | Label 09  | £100.00    |
+-----------+------------+-----------+------------+
| Label 05  | £100.00    | Label 10  | £100.00    |
+-----------+------------+-----------+------------+

We can use the slice filter to achieve this. See the following example:

.. thumbnail:: slice.png
   :align: center
   :width: 600

Notice that in the left column of the inner table we call slice with **start**
and **middle**, and in the right column we call slice with **middle** and
**end**.

See :download:`slice.docx`