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Variable Modifiers

Variable modifiers can be applied to variables, custom functions or strings. To apply a modifier, specify the value followed by a | (pipe) and the modifier name. A modifier may accept additional parameters that affect its behavior. These parameters follow the modifier name and are separated by a : (colon). Also, all php-functions can be used as modifiers implicitly (more below) and modifiers can be combined.


{* apply modifier to a variable *}

{* modifier with parameters *}

{* apply modifier to a function parameter *}
{html_table loop=$myvar|upper}

{* with parameters *}
{html_table loop=$myvar|truncate:40:"..."}

{* apply modifier to literal string *}

{* using date_format to format the current date *}

{* apply modifier to a custom function *}
{mailto|upper address=""}

{* using  php's str_repeat *}

{* php's count *}

{* this will uppercase and truncate the whole array *}
<select name="name_id">
{html_options output=$my_array|upper|truncate:20}
  • Modifiers can be applied to any type of variables, including arrays and objects.


    The default behavior was changed with Smarty 3. In Smarty 2.x, you had to use an "@" symbol to apply a modifier to an array, such as {$articleTitle|@count}. With Smarty 3, the "@" is no longer necessary, and is ignored.

    If you want a modifier to apply to each individual item of an array, you will either need to loop the array in the template, or provide for this functionality inside your modifier function.


    Second, in Smarty 2.x, modifiers were applied to the result of math expressions like {8+2}, meaning that {8+2|count_characters} would give 2, as 8+2=10 and 10 is two characters long. With Smarty 3, modifiers are applied to the variables or atomic expressions before executing the calculations, so since 2 is one character long, {8+2|count_characters} gives 9. To get the old result use parentheses like {(8+2)|count_characters}.

  • Modifiers are autoloaded from the $plugins_dir or can be registered explicitly with the registerPlugin() function. The later is useful for sharing a function between php scripts and smarty templates.

  • All php-functions can be used as modifiers implicitly, as demonstrated in the example above. However, using php-functions as modifiers has two little pitfalls:

    • First - sometimes the order of the function-parameters is not the desirable one. Formatting $foo with {"%2.f"|sprintf:$foo} actually works, but asks for the more intuitive, like {$foo|string_format:"%2.f"} that is provided by the Smarty distribution.

    • Secondly - if security is enabled, all php-functions that are to be used as modifiers have to be declared trusted in the $modifiers property of the security policy. See the Security section for details.

See also registerPlugin(), combining modifiers. and extending smarty with plugins