PHP快速入门（1）

时间：2010-10-18 来源：Aixe

# 注释 <?php
 // 介是单行注释
 /* 介是多行注释... */
 echo "This is something about php ";
?>

# 连接字符串 <?php
 $str1 = "You will see: ";
 $str2 = "How to concat strings.";
 echo "".$str1.$str2."";
?>

# 条件判断

代码 <?php
 $flag = true;
 if($flag)
 {
 echo "Under the condition...";
 }
 else
 {
 echo "Under other conditions...";
 }

 $val = 100;
 if($val == 0)
 {
 echo "It is zero.";
 }
 elseif($val < 0)
 {
 echo "It is a negative.";
 }
 else
 {
 echo "It is a positive.";
 }
?>

# 分支结构

代码 <?php
 $case = 10;
 $result = "";
 switch($case)
 {
 case 1:
 $result = "In case one.";
 break;
 case 2:
 $result = "In case two.";
 break;
 case 3:
 $result = "In case three.";
 break;
 default:
 $result = "In other case.";
 break;
 }
 echo "".$result."";
?>

# 三元运算 <?php
 $val = 1;
 $exp = ($val == 0) ? "The value is zero" : "The value is not zero";
 echo $exp;
?>

# 数组array

代码 <?php
 echo "<ul>";
 $arr1 = array("John", "Jane", "Julie");
 echo "<li>People in array #1: $arr1[0], $arr1[1], $arr1[2]</li>";

 $arr2 = array(0 => "Jodan", 1 => "Jack", 2 => "James");
 echo "<li>People in array #2: $arr2[0], $arr2[1], $arr2[2]</li>";

 $arr3 = array(1 => "Tom", "Sam", "Kim");
 echo "<li>People in array #3: $arr3[1], $arr3[2], $arr3[3]</li>";

 $arr4[3] = "Avril";
 $arr4[2] = "Taylor";
 $arr4[1] = "Miley";
 echo "<li>People in array #4: $arr4[1], $arr4[2], $arr4[3]</li>";
 echo "</ul>";
?>

# for循环和foreach

代码 <?php
 $fib[0] = 1;
 $fib[1] = 1;
 for($i = 2; $i < 10; $i++)
 {
 $fib[$i] = $fib[$i-1] + $fib[$i-2];
 }

 echo "The Fibonacci: ";
 foreach($fib as $index => $value)
 {
 echo (string)$value." ";
 }
 echo "";
?>

# while循环 <?php
 $n = 6;
 $c = 1;
 $r = 1;
 while($c <= $n)
 {
 $r *= $c;
 $c += 1;
 }
 echo "$n != $r ";
?>

# 函数和递归 <?php
 function factorial($val)
 {
 if($val == 0) return 1;
 return $val * factorial($val - 1);
 }
 $n = 7;
 echo "$n! = ".(string)factorial($n)."";
?>