PHP Switch vs. If/Else

gistfile1.aw

<?php

$iterations = 10000;
$options = array('apple', 'banana', 'carrot');
$color = NULL;

// Fill an array with random keys. This ensures
// that (a) we use the same keys, and (b)
// slowness in the randomizer doesn't impact the
// loops (which can happen if entropy collection kicks in)
$samples = array();
for ($i = 0; $i < $iterations; ++$i) {
  $samples[] = $options[rand(0, 2)];
}

// Test a switch statement.
$start_switch = microtime(TRUE);

for ($i = 0; $i < $iterations; ++$i) {
  $option = $samples[$i];
  switch ($option) {
    case 'apple':
      $color = 'red';
      break;
    case 'banana':
      $color = 'yellow';
      break;
    default:
      $color = 'green';
  }
}
$end_switch = microtime(TRUE);

$total_switch = $end_switch - $start_switch;
printf("Switch:\t%0.6f sec to process %d" . PHP_EOL, $total_switch, $iterations);

// Test an array lookup.
$start_map = microtime(TRUE);
for ($i = 0; $i < $iterations; ++$i) {
  $option = $samples[$i];
  if ('apple' == $option) {
    $color = 'red';
  }
  elseif ('banana' == $option) {
    $color = 'yellow';
  }
  else {
    $color = 'green';
  }
}
$end_map = microtime(TRUE);

$total_map = $end_map - $start_map;
printf("If:\t%0.6f sec to process %d" . PHP_EOL, $total_map, $iterations);

This is the wrong test. Of course, the if statement will be faster in option with three compares. But, what will happen when you increase the number of cases for switch & if. My, solution shows another result. Try it by yourself on PHP 7.2

<?php

$bar = 'bar';
$start = microtime(true);

if ($bar === 'foo') {
    $foo = 'foo';
} elseif ($bar === 'var') {
    $foo = 'var';
} elseif ($bar === 'let') {
    $foo = 'let';
} elseif ($bar === 'net') {
    $foo = 'net';
} else {
    $foo = 'bar';
}

$end = microtime(true);
printf('If: %0.6f sec to process' . PHP_EOL, $end - $start);

$start = microtime(true);

switch ($bar) {
    case 'foo':
        $foo = 'foo';
        break;
    case 'var':
        $foo = 'var';
        break;
    case 'let':
        $foo = 'let';
        break;
    case 'net':
        $foo = 'net';
        break;
    default:
        $foo = 'bar';
        break;
}

$end = microtime(true);
printf('Switch: %0.6f sec to process' . PHP_EOL, $end - $start);

I think to be sure for 100% you need to run both these tests in separated scripts.