在PHP中foreach的语法 [英] syntax for foreach in php

问题描述

这个语法在php中是什么意思？
$ b $ p $ foreach $ meta $ t = $ $ data $ >

上面的$ t => $ data是什么意思。

因为foreach基本上是（例如来自w3school）

 < ？php 
 $ colors = array（red，green，blue，yellow）; 
 foreach（$ colors为$ value）
 {
 echo$ value< br>; 
} 
？> 
  

上述情况下，$ value代表 $ t => $ data

$ colors 表示 $ meta code $
$ b $数组元$如下所示
$ b $ pre $ $ $ $ c > $ meta = Array（
'facebook'=> Array（
'title'=>'og：title'，
'type'=>'og：type'，
'url'=>'og：url'，
'thumbnail'=>'og：image'，
'width'=>'og：image：width'，
'height'=>'og：image：height'，
'sitename'=>'og：site_name'，
'key'=>'fb：admins'，
'description'=>'og：description'
），
'twitter'=> Array（
'card'=>'twitter：card'，
'description'=>'twitter：description'，
）
）;


那么$ t是什么，$ data是什么

如果我想在'脸谱'中获得'标题'作为一个单独的关键如何做到这一点。即。将

  $ t => $ data => $ final work 
 $ b $ t = facebook或twitter 
 $ data = title等
 $ final = og：title等
  

解决方案

阅读 http://www.php.net/manual/en/control-structures.foreach.php ，关注示例。

  / * foreach示例3：键和值* / 
 
 $ a = array（
one=> 1 ，
two=> 2，
three=> 3，
seventeen=> 17 
）; 
 
 foreach（$ a as $ k => $ v）{
 echo\ $ a [$ k] => $ v.\\\
; 
} 
 
 / * foreach示例4：多维数组* / 
 $ a = array（）; 
 $ a [0] [0] =a; 
 $ a [0] [1] =b; 
 $ a [1] [0] =y; 
 $ a [1] [1] =z; 
 $ b foreach（$ a as $ v1）{
 foreach（$ v1 as $ v2）{
 echo$ v2\\\
; 
 
 
 
 
 
 
 
如果你使用php编码阅读官方手册不是'all-around-sites'。 
 
 
 已添加  
 
 
 < code = $ a = array（
one=> 1，
two=> 2，
three=> 3，
 seventeen=> 17 
）; 
 
 foreach（$ a as $ k => $ v）{
 echo$ k => $ v; 
 //会显示
 // one => 1two => 2three => 3 
} 
 
 foreach（$ a as $ v）{
 echo$ v; 
 //会显示
 // 12317 
 
 code $ $ $ $ $ $ $ $ $ $ $ $ ，如果我们使用$ k（在我们的foreach（））中有'key'的名字。 $ v 
 
 pre pre $ p $数组（
'title'，&b; $ b'b'='>'$' 'og：type'，
'url'=>'og：url'，
'thumbnail'=>'og：image'，
'width'=>'og ：image：width'，
'height'=>'og：image：height'，
'sitename'=>'og：site_name'，
'key'=> 'fb：admins'，
'description'=>'og：description'
），
'twitter'=> Array（
'card'=>' twitter：card'，
'description'=>'twitter：description'，
）
）; 
 $ b foreach（$ meta as $ sKey => $ aValue）{
 // $ sKey =='facebook'
 // $ aValue = array（）$ b $ （$ aValue as $ sKeyInner => $ sValue）{
 // $ sKeyInner =='$ b $ title'
 // $ sValue =='og：title'
} 
} 
  
就这样，我放弃了。 XD 
 
what does this syntax means in php

foreach ( $meta as $t => $data )

what does $t => $data mean in the above. 

because foreach is basically (example from w3school)
  <?php
  $colors = array("red","green","blue","yellow");
  foreach ($colors as $value)
    {
    echo "$value <br>";
    }
  ?> 
it the above case $value represents $t => $data

$colors represents $meta

the array $meta is as follows
    $meta = Array(
    'facebook' => Array(
      'title'   => 'og:title',
      'type'   => 'og:type',
      'url'   => 'og:url',
      'thumbnail'  => 'og:image',
      'width'   => 'og:image:width',
      'height'  => 'og:image:height',
      'sitename'  => 'og:site_name',
      'key'   => 'fb:admins',
      'description' => 'og:description'
    ),
    'twitter' => Array(
      'card'   => 'twitter:card',
      'description' => 'twitter:description',
    )
      );
then what is $t and what is $data 

also if i want to get 'title' in 'facebook' as a seprate key how to do it. ie. will 
  $t => $data => $final work

  $t = facebook or twitter
  $data = title etc
  $final = og:title etc

解决方案
Read this http://www.php.net/manual/en/control-structures.foreach.php , attention on examples.
/* foreach example 3: key and value */

$a = array(
    "one" => 1,
    "two" => 2,
    "three" => 3,
    "seventeen" => 17
);

foreach ($a as $k => $v) {
    echo "\$a[$k] => $v.\n";
}

/* foreach example 4: multi-dimensional arrays */
$a = array();
$a[0][0] = "a";
$a[0][1] = "b";
$a[1][0] = "y";
$a[1][1] = "z";

foreach ($a as $v1) {
    foreach ($v1 as $v2) {
        echo "$v2\n";
    }
}
PS: If you coding using php read official manual not 'all-around-sites'.

ADDED
$a = array(
    "one" => 1,
    "two" => 2,
    "three" => 3,
    "seventeen" => 17
);

foreach ($a as $k => $v) {
    echo "$k => $v";
    // will show
    // one => 1two => 2three => 3
}

foreach ($a as $v) {
    echo "$v";
    // will show 
    // 12317
}
So, if we use $k (in our foreach()) we have 'key' name. In $v we always have 'value'.

ADDED
    $meta = Array(
        'facebook' => Array(
            'title' => 'og:title',
            'type' => 'og:type',
            'url' => 'og:url',
            'thumbnail' => 'og:image',
            'width' => 'og:image:width',
            'height' => 'og:image:height',
            'sitename' => 'og:site_name',
            'key' => 'fb:admins',
            'description' => 'og:description'
        ),
        'twitter' => Array(
            'card' => 'twitter:card',
            'description' => 'twitter:description',
        )
    );

    foreach ($meta as $sKey => $aValue) {
        // $sKey == 'facebook'
        // $aValue = array()
        // $aValue['title'] == 'og:title' 

        foreach ($aValue as $sKeyInner => $sValue) {
            // $sKeyInner == 'title'
            // $sValue == 'og:title'
        }
    }
That's all, I give up. XD

                        
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