mb_strtolower - PHP code example

The php Function mb_strtolower

If the world of PHP lowercase conversion is a bustling metropolis, then the php function mb_strtolower is the high-speed bullet train that smoothly glides through its streets, tackling special characters and accented letters with ease. It’s also the artisan of text handling, offering superior craftsmanship and skillfully crafting a beautiful string-handling masterpiece with every stroke.

The mb_strtolower function, which is available in PHP 4+ versions, converts the character set of a string into its lowercase counterpart. It takes only one parameter, $string, and returns the result. Unlike strtolower, it doesn’t depend on the locale (as set by setlocale()). However, if the argument is omitted or null, then internal character encoding will be used.

For those who prefer to craft their own custom tools, there are several excellent libraries that can help with the task of lowercase conversion, including the Symfony String Component, Laravel Str, and Patchwork UTF-8. They each offer versatile and reliable sidekicks that will get you through any text-handling obstacle with ease.

To truly master the craft of PHP lowercase conversion, thorough testing is key. By thoroughly testing your code with a diverse set of inputs, you can ensure that the results of your code will be as expected and free from any unexpected surprises. This will also help you identify any areas that may require further tweaking to meet your unique requirements.

mb_strtolower example

  protected function assertHtmlToText(string $html, string $text, string $message, ?array $allowed_tags = NULL): void {
    preg_match_all('/<([a-z0-6]+)/', mb_strtolower($html), $matches);
    $tested_tags = implode(', ', array_unique($matches[1]));
    $message .= ' (' . $tested_tags . ')';
    $result = MailFormatHelper::htmlToText($html, $allowed_tags);
    $this->assertEquals($text, $result, Html::escape($message));
  }

  /** * Tests supported tags of \Drupal\Core\Mail\MailFormatHelper::htmlToText(). */
  public function testTags() {
    global $base_path, $base_url;

return explode(' ', $text);
  }

  /** * {@inheritdoc} */
  public function analyze(string $text, ?string $langcode = NULL): string {
    // Decode entities to UTF-8.     $text = Html::decodeEntities($text);

    // Lowercase.     $text = mb_strtolower($text);

    // Remove diacritics.     $text = $this->transliteration->removeDiacritics($text);

    // Call an external processor for word handling.     $this->invokePreprocess($text, $langcode);

    // Simple CJK handling.     if ($this->configFactory->get('search.settings')->get('index.overlap_cjk')) {
      $text = preg_replace_callback('/[' . self::PREG_CLASS_CJK . ']+/u', [$this, 'expandCjk'], $text);
    }

  protected function setUp(): void {
    parent::setUp();

    $this->container->get('state')->set('entity_test.field_test_item', TRUE);
    $this->entityTypeManager->clearCachedDefinitions();

    $entity_type_id = 'entity_test_mulrev';
    $this->installEntitySchema($entity_type_id);

    $this->fieldName = mb_strtolower($this->randomMachineName());

    /** @var \Drupal\field\Entity\FieldStorageConfig $field_storage */
    FieldStorageConfig::create([
      'field_name' => $this->fieldName,
      'type' => 'field_test',
      'entity_type' => $entity_type_id,
      'cardinality' => 1,
    ])->save();

    FieldConfig::create([
      'entity_type' => $entity_type_id,

  protected function setUp(): void {
    parent::setUp();

    // Configure the theme system.     $this->installConfig(['system', 'field']);
    $this->installEntitySchema('entity_test_rev');
    $this->installEntitySchema('entity_test_label');

    $this->entityType = 'entity_test_rev';
    $this->bundle = $this->entityType;
    $this->fieldName = mb_strtolower($this->randomMachineName());

    $field_storage = FieldStorageConfig::create([
      'field_name' => $this->fieldName,
      'entity_type' => $this->entityType,
      'type' => 'string',
    ]);
    $field_storage->save();

    $instance = FieldConfig::create([
      'field_storage' => $field_storage,
      'bundle' => $this->bundle,

    /** * Gets the packager for the provided key, if registered. * * @throws LineItemGroupPackagerNotFoundException */
    public function getPackager(string $key): LineItemGroupPackagerInterface
    {
        /** @var LineItemGroupPackagerInterface $packager */
        foreach ($this->packagers as $packager) {
            if (mb_strtolower($packager->getKey()) === mb_strtolower($key)) {
                return $packager;
            }
        }

        throw new LineItemGroupPackagerNotFoundException($key);
    }

    /** * Gets a list of all registered sorters. */
    public function getSorters(): \Generator
    {

if (empty($string)) {
            return [];
        }
        if ($this->replaceUmlauts) {
            $string = str_replace(
                ['Ü', 'ü', 'ä', 'Ä', 'ö', 'Ö', 'ß'],
                ['Ue', 'ue', 'ae', 'Ae', 'oe', 'Oe', 'ss'],
                $string
            );
        }

        $string = mb_strtolower(html_entity_decode($string), 'UTF-8');

        if ($this->replaceNonLetters) {
            // Remove not required chars from string             $string = trim((string) preg_replace("/[^\pL_0-9]/u", ' ', $string));
        }

        // Parse string into array         $wordsTmp = preg_split('/ /', $string, -1, PREG_SPLIT_NO_EMPTY);
        if (!\is_array($wordsTmp)) {
            return [];
        }

return (string) $request->query->get('language');
        }

        // language was already set         if ($session->has('language') && \in_array((string) $session->get('language'), $this->installerLanguages, true)) {
            return (string) $session->get('language');
        }

        // get initial language from browser header         if ($request->headers->has('HTTP_ACCEPT_LANGUAGE')) {
            $browserLanguage = explode(',', $request->headers->get('HTTP_ACCEPT_LANGUAGE', ''));
            $browserLanguage = mb_strtolower(mb_substr($browserLanguage[0], 0, 2));

            if (\in_array($browserLanguage, $this->installerLanguages, true)) {
                $session->set('language', $browserLanguage);

                return $browserLanguage;
            }
        }

        $session->set('language', self::FALLBACK_LOCALE);

        return self::FALLBACK_LOCALE;
    }

static::assertFalse(Uuid::isValid('74d25156-60e6-444c-a177-a96e67ecfc5f'));
    }

    public function testUuidFormat(): void
    {
        for ($i = 0; $i < 100; ++$i) {
            $uuid = Uuid::randomHex();
            static::assertSame(32, mb_strlen($uuid));
            // In uuid 7 the version is at pos 13 and pos 17 is either 8, 9, a or b             static::assertSame('7', $uuid[12]);
            static::assertContains($uuid[16], ['8', '9', 'a', 'b']);
            static::assertTrue($uuid === mb_strtolower($uuid));
        }
    }
}

'mail' => 'foobar@example.com',
    ]);
    $admin_user->addRole($role->id());
    $admin_user->save();
    $normal_user = User::create([
      'name' => 'normal user',
      'mail' => 'normal@example.com',
    ]);
    $normal_user->save();

    // Add a "body" field with the text format.     $field_name = mb_strtolower($this->randomMachineName());
    $field_storage = FieldStorageConfig::create([
      'field_name' => $field_name,
      'entity_type' => 'entity_test',
      'type' => 'text',
    ]);
    $field_storage->save();
    FieldConfig::create([
      'field_storage' => $field_storage,
      'bundle' => 'entity_test',
    ])->save();

    $this->drupalLogin($admin_user);

    // Create the block cache for all languages.     foreach ($this->langcodes as $langcode) {
      $this->drupalGet('admin/structure/block', ['language' => $langcode]);
      $this->clickLink('Place block');
    }

    // Create a menu in the default language.     $edit['label'] = $this->randomMachineName();
    $edit['id'] = mb_strtolower($edit['label']);
    $this->drupalGet('admin/structure/menu/add');
    $this->submitForm($edit, 'Save');
    $this->assertSession()->pageTextContains('Menu ' . $edit['label'] . ' has been added.');

    // Check that the block is listed for all languages.     foreach ($this->langcodes as $langcode) {
      $this->drupalGet('admin/structure/block', ['language' => $langcode]);
      $this->clickLink('Place block');
      $this->assertSession()->pageTextContains($edit['label']);
    }
  }

}

'administer site configuration',
      'administer workspace fields',
      'administer workspace display',
      'administer workspace form display',
    ]);
    $this->drupalLogin($user);

    $this->drupalGet('admin/config/workflow/workspaces/fields');
    $this->assertSession()->statusCodeEquals(200);

    // Create a new filed.     $field_name = mb_strtolower($this->randomMachineName());
    $field_label = $this->randomMachineName();
    $edit = [
      'new_storage_type' => 'string',
      'label' => $field_label,
      'field_name' => $field_name,
    ];
    $this->drupalGet("admin/config/workflow/workspaces/fields/add-field");
    $this->submitForm($edit, 'Save and continue');
    $page = $this->getSession()->getPage();
    $page->pressButton('Save field settings');
    $page->pressButton('Save settings');

    // localize.drupal.org. It does not need to match the version exactly as the     // multi-lingual system will fallback.     \Drupal::service('file_system')->mkdir($this->publicFilesDirectory . '/translations', NULL, TRUE);
    file_put_contents($this->publicFilesDirectory . "/translations/drupal-8.0.0.{$this->defaultLangcode}.po", '');
    return $parameters;
  }

  /** * Tests the node type translation. */
  public function testNodeTypeTranslation() {
    $type = mb_strtolower($this->randomMachineName(16));
    $name = $this->randomString();
    $this->drupalLogin($this->adminUser);
    $this->drupalCreateContentType(['type' => $type, 'name' => $name]);

    // Translate the node type name.     $langcode = $this->additionalLangcodes[0];
    $translated_name = $langcode . '-' . $name;
    $edit = [
      "translation[config_names][node.type.$type][name]" => $translated_name,
    ];

$this->drupalLogin($admin_user);

    // Create content type, with underscores.     $type_name = strtolower($this->randomMachineName(8)) . '_test';
    $type = $this->drupalCreateContentType(['name' => $type_name, 'type' => $type_name]);
    $this->type = $type->id();

    // Create a default vocabulary.     $vocabulary = Vocabulary::create([
      'name' => $this->randomMachineName(),
      'description' => $this->randomMachineName(),
      'vid' => mb_strtolower($this->randomMachineName()),
      'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
      'help' => '',
      'nodes' => ['article' => 'article'],
      'weight' => mt_rand(0, 10),
    ]);
    $vocabulary->save();
    $this->vocabulary = $vocabulary->id();
  }

  /** * Tests switching view modes to use custom or 'default' settings'. */

    $this->adminUser = $this->drupalCreateUser([
      'access content',
      'bypass node access',
    ]);
    $this->contentAdminUser = $this->drupalCreateUser([
      'access content',
      'administer content types',
      'administer node fields',
    ]);

    // Add a custom field to the page content type.     $this->fieldName = mb_strtolower($this->randomMachineName() . '_field_name');
    FieldStorageConfig::create([
      'field_name' => $this->fieldName,
      'entity_type' => 'node',
      'type' => 'text',
    ])->save();
    FieldConfig::create([
      'field_name' => $this->fieldName,
      'entity_type' => 'node',
      'bundle' => 'page',
    ])->save();
    /** @var \Drupal\Core\Entity\EntityDisplayRepositoryInterface $display_repository */

'placeholder' => [
                    'en-GB' => 'Type a text...',
                ],
                'customFieldPosition' => 1,
            ],
        };

        \assert(\is_string($name));

        return [
            'id' => Uuid::randomHex(),
            'name' => mb_strtolower($prefix) . '_' . str_replace(' ', '_', $name),
            'type' => $type,
            'config' => $config,
        ];
    }

    /** * @param array<string, mixed> $options */
    private function generateCustomFieldSet(array $options, DemodataContext $context): void
    {
        $relationNames = array_keys($options['relations']);