php 基础笔记 - functions-优快云博客

本文通过几个具体的PHP代码示例，介绍了PHP中函数定义与调用的方法，包括递归函数、数组作为参数传递、按引用传递参数、默认参数设置等高级特性，并展示了变量函数和变量方法的使用。

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/***************************by garcon1986********************************/

<?php //example1 $makefoo = true; bar(); if($makefoo){ function foo(){ echo "doesn't exist. "; } } if($makefoo)foo(); function bar(){ echo "exist "; } //example2 function sjg(){ function wl(){ echo 'must call sjg() before wl()! '; } } sjg(); wl(); //wl(); //sjg(); //example3 - 递归 $a = 10; function recursion($a){ if($a <= 20){ echo "$a/n"; recursion($a+1); } } recursion($a); echo " "; //example4 - 向函数传递数组 $input1=array('hi','ni','hao','ya'); function record($input1){ echo $input1[0],$input1[1],$input1[2]; } record($input1); //pass the function's parameter by reference function add_some_extra(&$string){ $string .= 'wl wo ai ni.'; } $str1 = 'wo xiang shuo,'; add_some_extra($str1); echo $str1.' '; //output: wo xiang shuo, wl wo ai ni. //default parameter 默认参数 function makecoffee($category = "cappuccino"){ //return "makeing a cup of $category./n"; echo "making a cup of $category"; } echo makecoffee().' '; echo makecoffee("espresso").' '; // add one more parameter function makeyogurt($type = "acidophilus", $flavour) { return "making a bowl of $type and $flavour/n".' '; //return "Makin a bowl of $flavour/n"; } echo makeyogurt("","raspberry"); // won't work as expected //echo makeyogurt(); function makeyogurt2($flavour,$type = "acidophilus") { //return "making a bowl of $type and $flavour/n".' '; return "Makin a bowl of $flavour $type/n"; } echo makeyogurt2("raspberry").' '; // will work as expected //return 示例 function square($num){ return $num * $num; } echo square(4).''; function small_numbers(){ return array(0,1,2); } list($zero,$one,$two) = small_numbers(); echo $zero,$one,$two.''; function &returns_reference(){ return $someref; } $newref = & returns_reference(); echo $newref; //变量函数 function foo2(){ echo "in foo2() /n"; } function bar2($args=''){ echo "in bar2(); argument was '$args'. /n"; } function echoit($string){ echo $string.' '; } function lm(){ echo "wxryy. "; } $func = 'foo2'; $func(); $func = 'bar2'; $func('test'); $func = 'echoit'; $func('test'); $funct = 'lm'; $funct('wl'); // variable method class Foo{ function Variable(){ $name = 'Bar3'; $this->$name(); // this calls to Bar3 } function Bar3() { echo "This is Bar3"; } } $foo = new Foo(); $functname = "Variable"; $foo->$functname(); // this calls $foo->Variable() ?>