Most Efficient Way to Parse Array Into HTML Structure - php

Question

For the sake of simplicity let's say I have the following array:
$a = array();
$a[0]['lab'] = 1;
$a[0]['name'] = 'test1';
$a[1]['lab'] = 1;
$a[1]['name'] = 'test2';
$a[2]['lab'] = 2;
$a[2]['name'] = 'test3';
$a[3]['lab'] = 2;
$a[3]['name'] = "test4";
$a[4]['lab'] = 2;
$a[4]['name'] = "test5";
Keep in mind that the length of that array is completely variable and the number of items associated with each lab can vary as well. There might be one per lab there might be 100.
My desired HTML structure is the following:
<div class="parent"> <!-- Records for lab == 1 -->
<div class="child">test1</div>
<div class="child">test2</div>
</div>
<div class="parent"> <!-- Records for lab == 2 -->
<div class="child">test3</div>
<div class="child">test4</div>
<div class="child">test5</div>
</div>
I currently have a for loop with a bunch of extra logic now which is ugly/inefficient and occasionally misses the closing tag for the last "parent" div. I know there is a far more elegant way to do this and I would love to see what others have come up with.
** Edit:
Here is the logic I have in place now which is actually working for the test cases I have thrown at it but it looks horrible:
<?php
$labId = 0;
for($i = 0; $i < count(a); $i++)
{
if(($i+1) < count($a)) { $j = $i + 1;}
if($labId == 0 || $labId != $a[$i]['lab'])
{
echo '<div class="parent">';
}
echo '<div class="child">'.$a['name'].'</div>';
if(($a[$j]['lab'] != $labId && $a[$i]['lab'] != $labId && $labId != 0) || count($a) == 1)
{
echo '</div>';
}
$labId = $a[$i]['lab'];
}
?>

Answer 1

I would do it like this:
$a = ... // copied from your code
$newArray = array();
foreach($a as $e){
$newArray[$e['lab']][] = $e['name'];
}
foreach($newArray as $lab){
echo "<div class=\"parent\">\n";
foreach($lab as $child){
echo "\t<div class=\"child\">".$child."</div>\n";
}
echo "</div>\n";
}
Hope that's simple enough.

Answer 2

The code below should do the trick without creating a new array
foreach ($a as $key0 => $labs) {
foreach ($labs as $key1 => $value) {
if ($key1 == 'lab') {
echo '<div class="parent">';
} else {
echo '<div class="child">'.$value.'</div>';
}
}
//Close parent divs
if (isset($key0['lab'])) {
echo '</div>';
}
}

Answer 3

My solution was somewhat of a combination of the responses and some other trial and error.
<?php
// define original test array
$a = array();
$a[0]['lab'] = 1;
$a[0]['name'] = 'test1';
$a[1]['lab'] = 1;
$a[1]['name'] = 'test2';
$a[2]['lab'] = 2;
$a[2]['name'] = 'test3';
$a[3]['lab'] = 2;
$a[3]['name'] = "test4";
$a[4]['lab'] = 2;
$a[4]['name'] = "test5";
// new array has to be defined outside the foreach() loop, or it will be treated as a local var
$anew = array();
// for each entry, assign to $anew[lab#][next_avail_entry#]['name'] = <value>
foreach ($a as $arec)
$anew[$arec['lab']][]['name'] = $arec['name'];
// output: one parent div for each lab, plus subdivs for as many values as are avail for each lab
foreach ($anew as $alab)
{
printf("<div class=\"parent\">\n");
foreach ($alab as $arec)
printf(" <div class=\"child\">%s</div>\n", $arec['name']);
printf("</div>\n");
}
?>
* Edit: One other solution I found was to query for the labs and items separately and loop through the lab as the outer loop and the items as an inner foreach loop.