Help me combine these conditions for determining if this list item begins with a new letter

Question

Maybe I'm having a bad day, but I can't seem to combine these 2 conditions into 1. They obviously should be, because they output the exact same data. The following code creates a list with A-Z to act as anchor links, and is then meant to traverse an array in the format 'word'=>'definition'. I wanted the PHP to output a h3 element with the current letter everytime it detected a new letter.

Here is what I have

    $letters = range('A', 'Z');
    echo '<em>Jump to:</em><ul class="letters">';
    // anchors
    foreach ($letters as $letter) {            
        echo '<li><a href="#botany-words-' . $letter . '">' . $letter . '</a></li>';      
    }        
    echo '</ul>';        
    // start listing them!        
    $currentLetter = 0;        
    echo '<dl id="botany-words">';

    foreach($content as $botanyWord=>$definition) {

         if ($botanyWord == key(array_slice($content, 0, 1))) { // must be first, aka 'A'

             echo '<h3 id="botany-words-' . $letters[$currentLetter] . '">' . $letters[$currentLetter] . '</h3>';


         } 

        if (substr($botanyWord, 0, 1) != $letters[$currentLetter]) {  // if the first character of this botany word is different to the last              
            echo '<h3 id="botany-words-' . $letters[$currentLetter] . '">' . $letters[$currentLetter] . '</h3>';

            $currentLetter++;
        }
    ?>

        <dt><?php echo $botanyWord; ?></dt>
        <dd><?php // echo $definition; ?></dd>

    <?
    }
    echo '</dl>';

Everytime I tried to do

if ($botanyWord == key(array_slice($content, 0, 1)) || substr($botanyWord, 0, 1) != $letters[$currentLetter])

it didn't work right, and error'd because it overflowed the 26th index (obviously being 26 chars in the alphabet).

Thank you for your assistance!

Answer 1

$currentLetter = '';
foreach($content as $botanyWord=>$definition) {
  if ( $currentLetter !== $botanyWord[0] ) {
    $currentLetter = $botanyWord[0];
    // next letter ...if your array is in lex. order
    ...
  }
  ...
}