ThinkPHP template judgment output Present label usage details _ PHP Tutorial

The usage of the output Present tag determined by the ThinkPHP template is described in detail. The present tag of the ThinkPHP template is used to determine whether the template variable has been assigned a value. The present tag of the ThinkPHP template engine is used to determine whether the template variable has been assigned a value. its function is equivalent to the present tag of the PH ThinkPHP template. Determine whether the template variable has been assigned a value.

The present tag of the ThinkPHP template engine is used to determine whether the template variable has been assigned a value,Its function is equivalent to the isset () function behavior in PHP.The format is as follows:

 
  
Content to be output
 

Examples:

 
  
{$ Username} Hello!
 

This example is equivalent:

If (isset ($ username) {echo "$ username Hello! ";}

In addition, the notpresent label can be used to judge whether no value is assigned. the usage is as follows:

 
  
The username does not exist. the user is not logged on.
 

You can also merge the preceding two labels:

 
  
{$ Username} Hello!
  The username does not exist. the user is not logged on.
 

Locate to determine whether the template variable has been assigned a value. The present tag of the ThinkPHP template engine is used to determine whether the template variable has been assigned a value. its function is equivalent to PH...