php学习（1）

php的简单定义：
      PHP是一种服务器端HTML-嵌入式脚本描述语言。

php基本语法：

• php 数组

a. 数组的创建和赋值

    <?php      $arr = array();      $arr['t1'] = 'test1';      $arr['t2'] = 'test2';      $arr['t3'] = 'test3';      print_r( $arr['t1'].$arr['t2'].$arr['t3']);    ?>     <br>    <?php      $vegetables =  array();      $vegetables[0] = "yellow";      $vegetables[1] = "red";      $vegetables[2] = "orange";      echo $vegetables[0];    ?>     <br>    <?php      $vegetables =  array("a"=> "abc","b"=>"black","c"=>"color");      echo $vegetables["a"];    ?>

数组demo：

 <?php        $row_color = array('red','green');        $color_index = 0;        $meal = array('早餐'=>'油条,鸡蛋,豆浆',                      '午餐'=>'套餐,快餐',                      '晚餐'=>'沙拉,香槟,拉面',                      '夜宵'=>"混沌,烤肉串");        print '<table border="1"><caption>本店提供</caption>';        foreach($meal as $key => $value){            print "<tr bgcolor='".$row_color[$color_index]."'>";            print "<td>$key</td><td>$value</td></tr>";            $color_index = 1 - $color_index;        }        print "</table>";     ?>

效果截图：

b. 判断数组中是否存在键值

   // demo1   <?php    $meals = array('面条',        '馒头',    '饺子',    '大饼'    );    echo "<br>";    if(in_array('面条',$meals)){    print $meals[0];    }    ?>    // demo2     <?php        $meals = array('面条'=>5.0,                       '馒头'=>2.0,                       '饺子'=>8.0,                       '大饼'=>3.0,        );        $books = array('book1','author');       if(array_key_exists('面条',$meals)){           print "吃面条<br/>";       }      if(array_key_exists('饺子',$meals)){          print "吃饺子<br/>";      }      if(array_key_exists(1,$books)){          print  $books[0]."的作者是:".$books[1]."";      }      ?>

c.数组的遍历

<!--数组的遍历--><?php  $arr = array('面条','鸡蛋','油条');  for($i = 0;$i<count($arr);$i++){      echo $arr[$i]."<br>";  }  echo "<hr>";  foreach($arr as $value){      echo  $value."<br>";  }?>

d.利用implode把数组转换为字符串

<?php//利用implode来生成字符串$meals = array('面条', '馒头', '饺子', '大饼');echo implode('<><>',$meals);?>

转换结果：

面条<><>馒头<><>饺子<><>大饼

demo:

<?php//利用implode来生成字符串$meals = array('面条', '馒头', '饺子', '大饼');$price = array('18','19','20','20');echo "<table border='1'><tr><td>";echo implode('</td><td>',$meals)."</td></tr>";echo "<tr><td>".implode("</td><td>",$price)."</td></tr>";echo "</table>";?>

转换结果：

e.对数组进行排序

<?php$meals = array('面条', 'a馒头', '饺子', '大饼');$price = array('28','1','22','20');foreach($meals as $value ){    echo $value."<br>";}foreach($price as $value ){    echo $value."<br>";}sort($meals);sort($price);foreach($meals as $value ){    echo $value."<br>";}foreach($price as $value ){    echo $value."<br>";}?>