Details about how to use the ThinkPHP template to determine the output Present tag

This article mainly introduces the usage of the ThinkPHP template to determine the output Present tag, which can be used to determine whether the template variable has been assigned a value. if you need it, refer to ThinkPHP.

The present label of the ThinkPHP template is usedDetermine 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.