w3school的PHP教程提炼（一）PHP基础

w3school的PHP教程提炼（一）PHP基础

本笔记只提炼php需要注意的部分，关于运算符，简单判断等内容一概不写。

1 字符串

1.1 strlen()函数计算字符串长度

                  <p class="sycode">                 <?     php     echo           strlen     (     "     hello world!     "     );     ?>                  </p>

1.2 strops()函数在字符串内检索字符串或字符

                  <p class="sycode">                 <?     php     echo           strpos     (     "     hello world     "     ,     "     world     "     );     ?>                  </p>

2 数组

2.1 数值数组 带有数字ID键的数组

自动分配ID键：

                  <p class="sycode">                      $names           =           array     (     "     a     "     ,     "     b     "     ,     "     c     "     );                  </p>

人工分配ID键：

                  <p class="sycode">                      $names     [     0     ]      =           "     a     "     ;     $names     [     1     ]      =           "     b     "     ;     $names     [     2     ]      =           "     c     "     ;                  </p>

使用ID键：

                  <p class="sycode">                      <?     php     echo           $names     [     0     ]      .           "      &      "           .           $names     [     1     ]      .           "      &      "           .           $names     [     2     ];     ?>                  </p>

2.2 关联数组 数组中的每个ID键关联一个值

将值作为键分配：

                  <p class="sycode">                      $ages           =           array     (     "     a     "     =>     10     ,     "     b     "     =>     20     ,     "     c     "     =>     30     );                  </p>

另一种方法：

                  <p class="sycode">                      $ages     [     "     a     "     ]      =           "     10     "     ;     $ages     [     "     b     "     ]      =           "     20     "     ;     $ages     [     "     c     "     ]      =           "     30     "     ;                  </p>

使用ID键：

                  <p class="sycode">                      <?     php     echo           "     a is     "           .           $ages     [     "     a     "     ]      .           "     years old.     "     ;     ?>                  </p>

2.3 多维数组 包含一个或多个数组的数组（略）

3 循环

3.1 while

                  <p class="sycode">                      <?     php     $i     =     1     ;     while     (     $i     <=     5     ){     echo           "     the number is     "           .           $i           .           "     <br />     "          $i     ++     ;}     ?>                  </p>

3.2 do...while

                  <p class="sycode">                      <?     php     $i     =     0     ;     do     {     $i     ++     ;     echo           "     the number is     "           .           $i           .           "     <br />     "     ;}     while     (     $i     <     5     );     ?>                  </p>

3.3 for

                  <p class="sycode">                      <?     php     for     (     $i     =     1     ;     $i     <=     5     ;     $i     ++     ){     echo           "     hello world!<br />     "     ;}     ?>                  </p>

3.4 foreach

foreach语句用于循环遍历数组，每进行一次循环，当前数组元素的值就会被赋值给value变量（数组指针会逐一地移动）以此类推。

语法

                  <p class="sycode">                      foreach     (     array           as      value){     //     ...          }                  </p>

示例：输出给定数组的值

                  <p class="sycode">                      <?     php     $arr           =           array     (     "     one     "     ,     "     two     "     ,     "     three     "     );     foreach     (     $arr           as           $value     ){     echo           "     value:     "           .           $value           .           "     <br />     "     ;}     ?>                  </p>

4 函数

4.1 传递参数

                  <p class="sycode">                      <?     php     function      writeName(     $firstname     ,     $lastname     ){     echo           $firstname           .           $lastname           .           "     <br />     "     ;}     echo           "     my name is      "     ;writeName(     "     Gang     "     ,     "     Li     "     );     echo           "     my name is      "     writeName(     "     San     "     ,     "     Zhang     "     );     ?>                  </p>

4.2 返回值

                  <p class="sycode">                      <?     php     function      add(     $x     ,     $y     ){     $total           =           $x           +           $y     ;     return           $total     ;}     echo           "     1 + 2 =      "           .      add(     1     ,     2     );      //     print 1 + 2 = 3          ?>                  </p>

5 表单处理

$_GET变量用于收集来自method="get"的表单的值。

$_POST变量用于收集来自method="post"的表单的值。

5.1 $_GET变量

form.php

                  <p class="sycode">                      <     form      action     ="welcome.php"      method     ="get"     >     Name:     <     input      type     ="text"      name     ="name"           />     Age:     <     input      type     ="text"      name     ="age"           />          <     input      type     ="submit"           />          </     form     >                  </p>

welcome.php

                  <p class="sycode">                      Welcome      <?     php      echo           $_GET     [     "     name     "     ];      ?>.<     br      />     You are      <?     php      echo           $_GET     [     "     age     "     ];      ?>      years old     !                  </p>

 

5.2 $_POST变量

与$_GET不同之处在于：

$_POST没有发送信息量限制，而$_GET限制100字符

$_POST不在url处体现表单中的值，而$_GET传递的url可以加入收藏夹

 

5.3 $_REQUEST变量

$_REQUEST变量可用来取得通过get和post方法发送到表单数据的结果