Thinkphp User-Defined Function solves the addition and subtraction operation of template labels

In actual projects, we often need to add or subtract tag variables. However, in thinkphp, direct operations on Template variables are not supported.
Fortunately, it provides methods for user-defined functions. We can solve this problem using user-defined functions:
The syntax of the thinkphp template custom function is as follows:
Format: {: function (...)} (Refer to official help documentation: http://thinkphp.cn/Manual/196)

Use this to try addition and subtraction.
1. define functions in thinkphp. Create a common. php file in the common folder of the project (the system will automatically load the file ). Define two functions:

/*** Add, for the template to use * @ Param <type> $ A * @ Param <type> $ B * @ Author: liufangfang.net@gmail.com */function template_add ($, $ B) {echo (intval ($ A) + intval ($ B) ;}/ *** subtract, for template use * @ Param <type> $ A * @ Param <type> $ B * @ Author: liufangfang.net@gmail.com */function template_substract ($ A, $ B) {echo (intval ($ A)-intval ($ B ));}

2. Use functions in the template:

{: Template_add ($ var1, $ var2 )}
The sum of the variable var1 and var2.
Note that if the variable is an array, it should be displayed as follows:
{: Template_add ($ var [var1], $ var [var2])}
Instead, we usually use the dot syntax.