How to change class of first echo result in PHP?

I would suggest you to use a counter.. Not sure if this is the right way to do it..

Change your foreach as follows

$i=0;foreach($categories as $category) {  if($i==0)    echo '<li class="selected"><a data-content="' . $category->slug . '" href="#' . $category->slug . '">' . $category->name . '</a></li>';  else    echo '<li><a data-content="' . $category->slug . '" href="#' . $category->slug . '">' . $category->name . '</a></li>';  $i++;  }

OR

As suggested in the answer here, you could use array_shift() to process the first item in the array separatley.

That is, do it as below

$first = array_shift($categories);echo '<li class="selected"><a data-content="' . $first ->slug . '" href="#' . $first ->slug . '">' . $first ->name . '</a></li>';foreach($categories as $category) {  echo '<li><a data-content="' . $category->slug . '" href="#' . $category->slug . '">' . $category->name . '</a></li>';}

Read more about array_shift() in the docs

Lal's solution will work fine (as long as you increment $i), but here's a simpler way to do it without an extra variable for the counter :

foreach($categories as $index => $category){   if(!$index) echo "This is the first element";   else echo "This is not the first element";}

(not sure if this should be an edit or an answer since it's basically the same method but with a slightly simpler synthax, I'll post as an answer for now)

You can use this syntax for foreach. Using this syntax you have in $k the index of the iteration, while in $v the value of the array you're iterating. So if $k == 0 you're in the first iteration.

$a = array("first", "second", "third", "fourth");foreach ($a as $k=>$v) {    echo $k . "--->" . $v ;    if($k == 0){        echo "First iteration!";        //Do your stuff     }    echo "<br>";}