PHP - Create UL Nested Lists From Flatfile

Question

(Before anyone asks... I cannot use a MySQL database for this project.)

Using PHP, I need to create nested UL's from a flatfile database. The issue that I'm having is that I don't want duplicate items displayed. I could explain further, but if you'll take a look at the code below, you'll see the data and the goal. Thanks.

FLATFILE DATA:

section|category|service
Section One|Category One|
Section One|Category Two|SC1
Section One|Category Two|SC2
Section One|Category Two|SC3
Section One|Category Two|SC4
Section One|Category Three|
Section Two|Category Four|SC5
Section Two|Category Four|SC6
Section Three|Category Five|SC7

HTML GOAL OUTPUT:

<ul class="section">
    <li>Section One
        <ul class="category">
            <li>Category One</li>
                <!-- no service -->
        </ul> <!-- /category -->
        <ul class="category">
            <li>Category Two</li>
                <ul class="service">
                    <li>SC1</li>
                    <li>SC2</li>
                    <li>SC3</li>
                    <li>SC4</li>
                </ul> <!-- /service -->
            </li>
        </ul> <!-- /category -->
        <ul class="category">
            <li>Category Three</li>
                <!-- no service -->
        </ul> <!-- /category -->
    </li>
</ul> <!-- /section -->

<ul class="section">
    <li>Section Two
        <ul class="category">
            <li>Category Four</li>
                <ul class="service">
                    <li>SC5</li>
                    <li>SC6</li>
                </ul> <!-- /service -->
            </li>
        </ul> <!-- /category -->
    </li>
</ul> <!-- /section -->

<ul class="section">
    <li>Section Three
        <ul class="category">
            <li>Category Five</li>
                <ul class="service">
                    <li>SC7</li>
                </ul> <!-- /service -->
            </li>
        </ul> <!-- /category -->
    </li>
</ul> <!-- /section -->

My 1st attempt... thinking that I need to first check if the "section" exists, then assign the current "section" to a "section_last" to compare the next "section" with the current "section" value ... and if not, print the "section" ... and then onto the category. I didn't code the "service" value section because I wasn't haven't any success with the section & category values. It seems that I'm having an issue with either the 'logic' behind this or maybe there's a method for comparing the past value in the loop with the next value that PHP offers that I'm missing.

After seeing the example code from @Kyle S, I may be on a completely incorrect path for coding this.

<?php 
$section = '';
$category = '';
$service = '';
$section_last = '';
$category_last = '';
$service_last = '';

$x = 0;

$file = fopen("categories_data.txt", "r");
if (!$file) { echo 'ERROR: Unable to open file: <strong>'.$file.'</strong>'; }
fgets($file); // IGNORE FIRST LINE IN FLATFILE - column names

while (!feof($file) ) {
    $lines = fgets($file);
    $ele = explode('|', $lines);

    $section = $ele[0];
    $category = $ele[1];
    $service = $ele[2];

    $service = str_replace(array("\n", "\r", "\r\n", "\n\r"), '',$service);

    if(strlen($section)>0) {
        if(!($section == $section_last)) {
            echo '
    <ul>
        <li>'.$section;
            $section_last = $section;
            $x++;
        }
    }
    echo '
            <ul><li>'.$category.' > '.$service.'</li></ul>
';
        if($x) {
            if($section != $section_last) {
                echo '
        </li>
    </ul>
';
        }
    }


} // end $data_file WHILE

fclose($file);
?>

Could you add the code you've written to the question, please? What have you tried, and why didn't it work? — andrewsi, May 27 '13 at 17:17

Kyle · Answer 1 · 2013-05-27T17:44:31.080

I would suggest using nested arrays and checking if the service item exists using PHP's in_array function.

For example, to add a single line's worth of data, checking if the service exists first before doing so:

$data = explode("|", $line);
$section = $data[0];
$category = $data[1];
$service = $data[2];

if ( !array_key_exists($section, $tree) ) {
    $tree[$section] = array();
}

if ( !array_key_exists($category, $tree[$section]) ) {
    $tree[$section][$category] = array(); 
}

if ( !in_array($service, $tree[$section][$category]) ) {
    $tree[$section][$category][] = $service;
}

score 0 · Answer 2 · answered May 28 '13 at 09:05

I cannot take credit for this solution. I was answered on another site by an 'expert.' However, I really feel that this topic is important enough to repost this solution on this 'stack' site.

SOLUTION:

<?php
define('TAB', "\t");
define('TAB2', "\t\t");

// Open the input file 
$file = fopen('lines.csv', 'rt');
// ignore the first line 
fgets($file);
// Get the next line into an array splitting on the pipe 
$line = fgetcsv($file, 255, '|');

// set the initial section value 
$section = $line[0];
// Initialise batch array
$current = array();
// Loop through all lines in the file 
do {
// If this line contains a section that is not the same as the previous line then dump the last section
  if ($section != $line[0]) {
    dump_categories($current, $section);
// Set our section flag to the next section    
    $section = $line[0];
// Clear the array of batched items to dump    
    $current = array();
  }
// Add the line to the batch
  $current[] = $line;
} while($line = fgetcsv($file, 255, '|'));
// Remember to dump batch that has built up
dump_categories($current, $section);
fclose($file);

function dump_categories(& $lines, $section)
{
// Set our category flag
  $category = $lines[0][1];
// initialise batch array
  $current = array();
// Start a new seection  
  echo '<ul class="section">' . PHP_EOL;
  echo TAB . '<li>' . $section . PHP_EOL;
// If there are categories in this section then process them - don't want empty bullets here  
  if (!empty($lines[0][1])) {
    foreach($lines as $l) {
// if this is a new category then dump category and services for this category    
      if ($category != $l[1]) {
        dump_services($current, $category);
// set our category flag        
        $category = $l[1];
// ... and clear the batch array        
        $current = array();
      }
// add to batch      
      $current[] = $l;
    }
// and dump batched lines    
    dump_services($current, $category);
  }
  echo TAB . '</li>' . PHP_EOL;
  echo '</ul>';
}
// Services we assume is the end of the line so output the service if it exists.
function dump_services(& $lines, $category)
{
  echo TAB2 . '<ul class="category">' . PHP_EOL;
  echo TAB . TAB2 . '<li>' . $category . PHP_EOL;
  if (!empty($lines[0][2])) {
    echo TAB2 . TAB2 . '<ul class="service">' . PHP_EOL;
    foreach($lines as $l) {
      if (!empty($l)) {
        echo TAB . TAB2 . TAB2 . '<li>' . $l[2] . '</li>' . PHP_EOL;
      }
    }
    echo TAB2 . TAB2 . '</ul>' . PHP_EOL;
  }
  echo TAB . TAB2 . '</li>' . PHP_EOL;
  echo TAB2 . '</ul>' . PHP_EOL;
}
?>

PHP - Create UL Nested Lists From Flatfile

2 Answers2