break out of if and foreach

foreach($equipxml as $equip) {
    $current_device = $equip->xpath("name");
    if ( $current_device[0] == $device ) {
        // found a match in the file            
        $nodeid = $equip->id;
        break;
    }
}

Simply use break. That will do it.

A safer way to approach breaking a foreach or while loop in PHP is to nest an incrementing counter variable and if conditional inside of the original loop. This gives you tighter control than break; which can cause havoc elsewhere on a complicated page.

Example:

// Setup a counter
$ImageCounter = 0;

// Increment through repeater fields
while ( condition ):
  $ImageCounter++;

   // Only print the first while instance
   if ($ImageCounter == 1) {
    echo 'It worked just once';
   }

// Close while statement
endwhile;

if is not a loop structure, so you cannot "break out of it".

You can, however, break out of the foreach by simply calling break. In your example it has the desired effect:

$device = "wanted";
foreach($equipxml as $equip) {
    $current_device = $equip->xpath("name");
    if ( $current_device[0] == $device ) {
        // found a match in the file            
        $nodeid = $equip->id;

        // will leave the foreach loop and also the if statement
        break;
        some_function(); // never reached!
    }
    another_function();  // not executed after match/break
}

---

Just for completeness for others that stumble upon this question looking for an answer..

break takes an optional argument, which defines how many loop structures it should break. Example:

foreach (['1','2','3'] as $a) {
    echo "$a ";
    foreach (['3','2','1'] as $b) {
        echo "$b ";
        if ($a == $b) { 
            break 2;  // this will break both foreach loops
        }
    }
    echo ". ";  // never reached!
}
echo "!";

Resulting output:

1 3 2 1 !