&& performs a boolean And operation. Returns True if both parameters evaluate to True or False otherwise.

The left and right parameter to this symbol will be cast to boolean automatically. Integer or decimal values equal to 0, empty strings '', the string 'false', empty arrays, empty maps, and null are cast to False. All other values are cast to True.

[If: Left_Parameter && Right_Parameter]
  ...
[/If]

<?LassoScript
  If: Left_Parameter && Right_Parameter;
  ...
  /If;
?>