如何在PHP中执行循环（foreach）

Question

I am trying to scrape some strings (colors in the example below) but can only manage to scrape the first string (blue):

<?php

   function extract_unit($string, $start, $end)
   {
      $pos = stripos($string, $start);

      $str = substr($string, $pos);

      $str_two = substr($str, strlen($start));

      $second_pos = stripos($str_two, $end);

      $str_three = substr($str_two, 0, $second_pos);

      $unit = trim($str_three); // remove whitespaces

      return $unit;
    }   


// example to extract the colors 

$text = '<p>this is the color blue</p><p>this is the color yellow</p><p>this is the color red</p>';
$unit = extract_unit($text, 'color', '</p>');

// Outputs: blue, but I need yellow and red as well!
echo $unit;
?>

The above works but only outputs: blue, but I need yellow and red as well!

 foreach( $unit as $item )
{
    echo $item.'<br />';
}

This did not work, any ideas? Thanks!

Answer 1

From what I understand, you want to go through some HTML and grab each item inside of the <p> tags, and take what's after color to grab the specific word.

This is specifically for this situation but could easily be changed.

$text = '<p>this is the color blue</p><p>this is the color yellow</p><p>this is the color red</p>';
$unit = explode("<p>",$text); //Use PHP explode function
foreach($unit as $item){
  if($item != ""){ //If it's not empty
    $item = explode("color",$item); //explode() creates array
    $item = end($item); //Grab last element of array
    $item = trim($item); //Trim whitespace
    $item = strip_tags($item); //Remove the p tags
    echo $item."<br>"; //Echo out the color
  }
}

More info on PHP Explode: http://php.net/manual/en/function.explode.php