is_null
Summary
Returns TRUE if the provided variable is NULL.Usage
input|is_null( target )
Parameters
Name | Type | Description | Required |
---|---|---|---|
target | any | The target variable. | Only if the input parameter is omitted. |
Returns
TRUE or FALSE.Description
This operator checks if the input parameter or the target variable is NULL. If it is, the operator will return TRUE, otherwise FALSE will be returned. If both the input parameter and the target variable are provided, it is the target variable that will be evaluated. Please note that an integer with a value of zero is not the same as NULL.
Examples
Example 1
{def $my_variable=3} {if $my_variable|is_null()} It is NULL. {else} It is not NULL. {/if}
The following output will be produced: "It is not NULL.".
Example 2
{def $my_variable=3} {if is_null( $my_variable )} It is NULL. {else} It is not NULL. {/if}
The following output will be produced: "It is not NULL.".
Example 3
{def $a=3 $b='Mobile instrument.'} {if $a|is_null( $b )} It is NULL. {else} It is not NULL. {/if}
The following output will be produced: "It is not NULL.".
Balazs Halasy (05/02/2004 12:34 pm)
Balazs Halasy (06/05/2005 7:25 am)
Comments
checking, if a textline has content
Friday 18 August 2006 9:00:49 am
Heiner
<p class="headline">{attribute_view_gui attribute=$node.object.data_map.headline}</p>
{/if}
checking, if an image has content
Friday 25 August 2006 5:11:49 pm
Heiner
<p class="headline">{attribute_view_gui attribute=$node.object.data_map.headline}</p>
{/if}
checking, if an XML Block has content
Friday 25 August 2006 5:16:37 pm
Heiner
{attribute_view_gui attribute=$node.object.data_map.body}
{/section}
Re: checking, if an XML Block has content
Tuesday 05 September 2006 8:39:36 am
Helle Andersen
Checking if a matrix has content
Tuesday 05 September 2006 8:41:30 am
Helle Andersen
{attribute_view_gui attribute=$node.object.data_map.xx}
{/section}
Checking if a time-date field has content
Tuesday 05 September 2006 8:43:14 am
Helle Andersen
{/section}