PHP数组多维

2018-02-22 16:40 更新

PHP教程 - PHP数组多维

多维数组可以有数组作为其值。

包含其他数组的数组是二维数组。如果这些数组也包含数组，那么顶层数组是一个三维数组，依此类推。

以下代码使用数组运算符([])创建二维阵列。第一级的关键是Java和PHP。


<?PHP
$book["Java"] = array("Name"=>"Java Book", "Price"=> 1.2, "OnSale"=>"No");
$book["PHP"] = array("Name"=>"PHP Book", "Price"=>5.3, "OnSale"=>"Yes");
var_dump($book);
?>

上面的代码生成以下结果。

示例 - 使用array()函数创建二维数组

以下脚本创建一个称为的简单二维数组$ myBooks，然后使用print_r()显示其内容。


<?php /*  ww w  .j  a va2 s.  co  m*/
  $myBooks = array( 
    array( 
      "title" =>  "Learn PHP from www.w3cschool.cn", 
      "author" =>  "www.w3cschool.cn", 
      "pubYear" =>  2000 
    ), 
    array( 
      "title" =>  "Learn Java from www.w3cschool.cn", 
      "author" =>  "JavaAuthor", 
      "pubYear" =>  2001 
    ), 
    array( 
      "title" =>  "Learn HTML from www.w3cschool.cn", 
      "author" =>  "HTMLAuthor", 
      "pubYear" =>  2002 
    ), 
    array( 
      "title" =>  "Learn CSS from www.w3cschool.cn", 
      "author" =>  "CSSAuthor", 
      "pubYear" =>  2003 
    ), 
  ); 

  print_r ( $myBooks ); 
?>

上面的代码生成以下结果。

多维数组中的PHP访问元素

方括号语法可以访问a中的任何元素多维数组。

访问第一个维度

$multidimensionalArray[]

访问内部尺寸

$multidimensionalArray[][]

这里有些例子


<?php /*from w  ww  . j ava2  s  .  c o  m*/
  $myBooks = array( 
    array( 
      "title" =>  "Learn PHP from www.w3cschool.cn", 
      "author" =>  "www.w3cschool.cn", 
      "pubYear" =>  2000 
    ), 
    array( 
      "title" =>  "Learn Java from www.w3cschool.cn", 
      "author" =>  "JavaAuthor", 
      "pubYear" =>  2001 
    ), 
    array( 
      "title" =>  "Learn HTML from www.w3cschool.cn", 
      "author" =>  "HTMLAuthor", 
      "pubYear" =>  2002 
    ), 
    array( 
      "title" =>  "Learn CSS from www.w3cschool.cn", 
      "author" =>  "CSSAuthor", 
      "pubYear" =>  2003 
    ), 
  ); 
  print_r( $myBooks[1] ); 
  echo $myBooks[1]["title"] . "\n"; 
  echo $myBooks[3]["pubYear"] . "\n";   
?>

上面的代码生成以下结果。

PHP循环通过多维数组

多维数组基本上是嵌套在其他数组内的数组，我们可以使用嵌套循环通过多维数组！

我们可以使用以下嵌套的foreach语句循环通过多维数组。

foreach ( $myBooks as $book ) { 
   foreach ( $book as $key => $value ) { 

   } 
}

以下示例使用两个嵌套的foreach循环循环遍历$ myBooks数组。


<?php /* w  w w. java2s  .  c  o  m*/
   $myBooks = array( 
     array( 
       "title" => "Learn PHP from www.w3cschool.cn", 
       "author" => "www.w3cschool.cn", 
       "pubYear" => 2000 
     ), 
     array( 
       "title" => "Learn Java from www.w3cschool.cn", 
       "author" => "JavaAuthor", 
       "pubYear" => 2001 
     ), 
     array( 
       "title" => "Learn HTML from www.w3cschool.cn", 
       "author" => "HTMLAuthor", 
       "pubYear" => 2002 
     ), 
     array( 
       "title" => "Learn CSS from www.w3cschool.cn", 
       "author" => "CSSAuthor", 
       "pubYear" => 2003 
     ), 
    ); 

    $bookNum = 0; 

    foreach ( $myBooks as $book ) { 
     $bookNum++; 
     echo "Book #$bookNum:"; 
     foreach ( $book as $key => $value ) { 
       echo "$key :$value \n"; 
     } 
    } 
 ?>

上面的代码生成以下结果。