thinkphp Template judgment output empty label usage _php example

The empty label for the thinkphp template is used to determine whether the template variable is null.

The thinkphp template empty label is used to determine whether the template variable is null, and its function is equivalent to the empty () function behavior in PHP. The empty label uses the following format:

<empty name= "variable name" > What to Output </empty>

The specific usage is shown in the following example:

<empty name= "username" >username to null value </empty

This example is equivalent to:

<?php
if (empty ($username)) {
  echo ' username is a null value ';
}
? >

If you judge a Non-null value, you can use the Notempty label, as follows:

<notempty name= "username" >username not empty </notempty>

Two tags combined to write:

<empty name= "username" >username null value <else/>username NOT NULL </empty>