Empty
empty — Returns true if var does not exist or has a value that is empty or equal to zero, aka falsey, see conversion to boolean. Otherwise returns false..
Basic Usage:{if $myVar is empty}it's an empty variable{/if}{if $myVar|empty}it's an empty variable{/if}{if empty($myVar)}it's an empty variable{/if}{if $myVar is not empty}it's an not empty variable{/if}{if $myVar|empty:'!'}it's an not empty variable{/if}{if !empty($myVar)}it's an not empty variable{/if}