php foreach首先插入某个类，如果只有一个有不同的包

Question

My images folder has files format like below

    <img src='images/AAA_1.jpg'>
    <img src='images/AAA_2.jpg'>
    <img src='images/AAA_3.jpg'>
    <img src='images/BBB_1.jpg'>
    <img src='images/BBB_2.jpg'>
    <img src='images/BBB_3.jpg'>
    <img src='images/CCC_1.jpg'>
    <img src='images/DDD_1.jpg'>
    <img src='images/EEE_1.jpg'>
    <img src='images/EEE_2.jpg'>
......

my function is

function filter($contain){


    foreach ($carousel as $image) {

        if(strpos($image, $contain) === 0){
            $op = "<div class='box'><img src='imgs/$image'/></div>";
        }
    }

}

getallfiles is to get imgs folder files.

$name has AAA_, BBB_, CCC_, DDD_

How do I insert first class for each group, the output expecting is like below

<div class="box first"> 
    <img src='images/AAA_1.jpg'> 
</div>
<div class="box"> 
    <img src='images/AAA_2.jpg'> 
</div>
<div class="box"> 
    <img src='images/AAA_3.jpg'> 
</div>
<div class="box first"> 
    <img src='images/BBB_1.jpg'> 
</div>
<div class="box"> 
    <img src='images/BBB_2.jpg'> 
</div>
<div class="box"> 
    <img src='images/BBB_3.jpg'> 
</div>
<div class="box first"> 
    <img src='images/CCC_1.jpg'> 
</div>
<div class="box first"> 
    <img src='images/DDD_1.jpg'> 
</div> 

Answer 1

You need to set a variable before the loop which will help you determine whether the first for each letter has been set. You output that class the first time, then set that variable to something that will help you know not to output it again.

Using these arrays:

$carousel = array(
  'AAA_1.jpg',
  'AAA_2.jpg',
  'AAA_3.jpg',
  'BBB_1.jpg',
  'BBB_2.jpg',
  'BBB_3.jpg',
  'CCC_1.jpg'
);

$names = array('AAA_', 'BBB_', 'CCC_', 'DDD_');

... this function:

function filter($name){
    global $carousel;
    $found_first = false;
    foreach ($carousel as $image) {
       if(strpos($image, $name) === 0){
           $first = !$found_first ? ' first' : ''; // assign class if it's the first
           $found_first = true; // change the variable after the first loop
           $html = "<div class='box%s'><img src='imgs/%s'/></div>" . PHP_EOL;
           echo sprintf($html, $first, $image); // output formatted string
       }
    }
}

... and this loop:

foreach($names as $name) {
    filter($name);
}

... you get output like this:

<div class='box first'><img src='imgs/AAA_1.jpg'/></div>
<div class='box'><img src='imgs/AAA_2.jpg'/></div>
<div class='box'><img src='imgs/AAA_3.jpg'/></div>
<div class='box first'><img src='imgs/BBB_1.jpg'/></div>
<div class='box'><img src='imgs/BBB_2.jpg'/></div>
<div class='box'><img src='imgs/BBB_3.jpg'/></div>
<div class='box first'><img src='imgs/CCC_1.jpg'/></div>