Php UDF usage

Custom functions

7.2.1 Basic function naming principles:

1. The function name cannot be the same as the existing function name.

2. The function name can only contain letters, numbers, and underscores.

3. The function name cannot start with a number.

 

7.2.2 basic usage: declare with function

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<? Php // Create a function Function funcCountArea ($ radius) { Return $ radius * pi (); }   // Use the function $ Area = funcCountArea (20 ); Echo $ area; Echo '<br/> ';   $ Area2 = funcCountArea (30 ); Echo $ area2; ?>   Output 1256.63706144 2827.43338823

7.2.3 passing parameters by value

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<? Php $ A = 5; Function funcChange ($) { $ A = 2 * $; } FuncChange ($ ); Echo $; ?>   Output 5

 

7.2.4 passing parameters by reference

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<? Php $ A = 5; Function funcChange (& $) { $ A = 2 * $; } FuncChange ($ ); Echo $; ?>   Output 10

 

7.2.5 function call that returns multiple values

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<? Php Function funcUserInfo ($ username, $ password) { $ UserInfo = array ($ username, $ password ); Return $ userInfo; }   $ Arr = funcUserInfo ('anllin', '20140901 ');   Print_r ($ arr ); ?>   Output Array ([0] => anllin [1] => 123456)

 

 

7.2.6 another function call that returns multiple values (practical: recommended)

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<? Php Function funcUserInfo ($ username, $ password) { $ UserInfo [] = $ username; $ UserInfo [] = $ password; Return $ userInfo; }   $ Arr [] = funcUserInfo ('Bob', '123 '); $ Arr [] = funcUserInfo ('John', '123 '); $ Arr [] = funcUserInfo ('Mark', '123 '); Print_r ($ arr ); ?>   Output Array ([0] => Array ([0] => Bob [1] => 512655) [1] = & gt; Array ([0] = & gt; John [1] = & gt; 458736) [2] => Array ([0] => Mark [1] => 925472 ))

 

Note: function calls are case-insensitive, but variable names are case-sensitive.