if single word already output, continue

I'm very new in PHP, and would like to do a foreach loop that won't repeat a result if the same item has been output before.

Here's my code:

    foreach ( $attachments as $id => $attachment ) {
        echo ($attachment->post_title);
    }

As you can see, the word would be pulled by echo ($attachment->post_title);.

Is there a way to do some checking and avoid duplicates?

Many thank开发者_开发问答s for your help.

$outputted = array();

foreach($attachments as $id => $attachment) {
   if (!isset($outputted[$attachment->post_title])) {
      echo $attachment->post_title;
      $outputted[$attachment->post_title] = true;
   }
}

You could use array_unique like Rajesh suggested and not worry with making an extra array.

foreach ( array_unique($attachments) as $id => $attachment ) {
        echo ($attachment->post_title);
}

foreach ( $attachments as $id => $attachment ) {

         if (!isset($outputs[$attachment->post_title])){
            $outputs[$attachment->post_title] = true;
            echo ($attachment->post_title);
         }
}

you could do:

$output = array();

foreach ( $attachments as $id => $attachment ) {
    if (!isset($output[$attachment->post_title])){
        echo ($attachment->post_title);
        $output[$attachment->post_title] = true;
    }
}

Use associative arrays:

$used = array();
foreach ($attachments as $id => $attachment) {
    if (!array_key_exists($attachment->post_title, $used)) {
        $used[$attachment->post_title] = 1;
        echo $attachment->post_title;
    }
}

Maybe something like this?

foreach ( $attachments as $id => $attachment ) {
    $attachments_posted[] = $attachment;
    if (!array_search($attachment, $attachments_posted))
        echo ($attachment->post_title);
}

Use an array to keep track of which titles you've already seen:

$seen = array();
foreach ($attachments as $id => $attachment) {
    if (array_key_exists($attachment->post_title, $seen)) {
        continue;
    }
    $seen[$attachment->post_title] = true;
    echo $attachment->post_title;
}