strtolower - PHP code example

php Function Strtolower - Converting Special Characters and Accents With Ease

The php function strtolower is the ultimate tool for handling case conversion in your PHP code. Its simple syntax and real-life applications make it a must-have in every developer’s arsenal. But like any superhero, strtolower is not without its limitations. In fact, it can be downright dangerous to use with certain types of input.

Let’s take a closer look at how the php function strtolower works, and then we’ll discuss alternative methods for tackling the tricky special characters and accents that can trip up unsuspecting developers. We’ll also take a look at mb_strtolower, a newer function that tackles multibyte UTF-8 strings with ease.

When it comes to string casing, consistency is key. With that in mind, we’ll see how lcfirst and ucwords can complement the php function strtolower by working together to ensure consistent results across all of your strings.

The lcfirst() function is a predefined function in PHP that takes a string and returns the same string with its first character capitalized. This function is very similar to the php function strtolower, which converts all characters in a string to lowercase.

strtolower example

$this->io = $io;
    }

    public function get(string $name)
    {
        return $this->options[$name] ?? null;
    }

    public function expandTargetDir(string $target): string
    {
        return preg_replace_callback('{%(.+?)%}', function D$matches) {
            $option = str_replace('_', '-', strtolower($matches[1]));
            if (!isset($this->options[$option])) {
                return $matches[0];
            }

            return rtrim($this->options[$option], '/');
        }, $target);
    }

    public function shouldWriteFile(string $file, bool $overwrite): bool
    {
        if (isset($this->writtenFiles[$file])) {

        if (null === $test || !preg_match('#^\s*(==|!=|[<>]=?)?\s*([0-9\.]+)\s*([kmg]i?)?\s*$#i', $test, $matches)) {
            throw new \InvalidArgumentException(sprintf('Don\'t understand "%s" as a number test.', $test ?? 'null'));
        }

        $target = $matches[2];
        if (!is_numeric($target)) {
            throw new \InvalidArgumentException(sprintf('Invalid number "%s".', $target));
        }
        if (isset($matches[3])) {
            // magnitude             switch (strtolower($matches[3])) {
                case 'k':
                    $target *= 1000;
                    break;
                case 'ki':
                    $target *= 1024;
                    break;
                case 'm':
                    $target *= 1000000;
                    break;
                case 'mi':
                    $target *= 1024 * 1024;

    protected function _processSection($iniArray, $section, $config = array())
    {
        $thisSection = $iniArray[$section];

        foreach ($thisSection as $key => $value) {
            if (strtolower($key) == ';extends') {
                if (isset($iniArray[$value])) {
                    $this->_assertValidExtend($section, $value);

                    if (!$this->_skipExtends) {
                        $config = $this->_processSection($iniArray, $value, $config);
                    }
                } else {
                    /** * @see Zend_Config_Exception */
                    throw new Zend_Config_Exception("Parent section '$section' cannot be found");
                }

$path_so_far = array();
                foreach ($DirPieces as $key => $value) {
                    if (strpos($value, ' ') !== false) {
                        if (!empty($path_so_far)) {
                            $commandline = 'dir /x '.escapeshellarg(implode(DIRECTORY_SEPARATOR, $path_so_far));
                            $dir_listing = `$commandline`;
                            $lines = explode("\n", $dir_listing);
                            foreach ($lines as $line) {
                                $line = trim($line);
                                if (preg_match('#^([0-9/]{10}) +([0-9:]{4,5}( [AP]M)?) +(<DIR>|[0-9,]+) +([^ ]{0,11}) +(.+)$#', $line, $matches)) {
                                    list($dummy, $date, $time, $ampm, $filesize, $shortname, $filename) = $matches;
                                    if ((strtoupper($filesize) == '<DIR>') && (strtolower($filename) == strtolower($value))) {
                                        $value = $shortname;
                                    }
                                }
                            }
                        } else {
                            $this->startup_warning .= 'GETID3_HELPERAPPSDIR must not have any spaces in it - use 8dot3 naming convention if neccesary. You can run "dir /x" from the commandline to see the correct 8.3-style names.'."\n";
                        }
                    }
                    $path_so_far[] = $value;
                }
                $helperappsdir = implode(DIRECTORY_SEPARATOR, $path_so_far);
            }

$orderResult = $this->orderRepository->search($criteria, $context->getContext());
        $orders = $orderResult->getEntities();

        // remove old orders only if there is a deeplink filter         if ($deepLinkFilter !== null) {
            $orders = $this->filterOldOrders($orders);
        }

        // Handle guest authentication if deeplink is set         if (!$context->getCustomer() && $deepLinkFilter instanceof EqualsFilter) {
            try {
                $cacheKey = strtolower((string) $deepLinkFilter->getValue()) . '-' . $request->getClientIp();

                $this->rateLimiter->ensureAccepted(RateLimiter::GUEST_LOGIN, $cacheKey);
            } catch (RateLimitExceededException $exception) {
                throw OrderException::customerAuthThrottledException($exception->getWaitTime(), $exception);
            }

            $order = $orders->first();
            $this->checkGuestAuth($order, $request);
        }

        if (isset($cacheKey)) {

/** * Creates a cookie copy with SameSite attribute. * * @param self::SAMESITE_*|''|null $sameSite */
    public function withSameSite(?string $sameSite): static
    {
        if ('' === $sameSite) {
            $sameSite = null;
        } elseif (null !== $sameSite) {
            $sameSite = strtolower($sameSite);
        }

        if (!\in_array($sameSite, [self::SAMESITE_LAX, self::SAMESITE_STRICT, self::SAMESITE_NONE, null], true)) {
            throw new \InvalidArgumentException('The "sameSite" parameter value is not valid.');
        }

        $cookie = clone $this;
        $cookie->sameSite = $sameSite;

        return $cookie;
    }

if ('' !== $string && $this->ignoreCase) {
            return 0 === strcasecmp($string, $this->string);
        }

        return $string === $this->string;
    }

    public function folded(): static
    {
        $str = clone $this;
        $str->string = strtolower($str->string);

        return $str;
    }

    public function indexOf(string|iterable|AbstractString $needle, int $offset = 0): ?int
    {
        if ($needle instanceof AbstractString) {
            $needle = $needle->string;
        } elseif (!\is_string($needle)) {
            return parent::indexOf($needle, $offset);
        }

/** * Tests creating a view of workspace entities. * * @see \Drupal\views\Plugin\views\wizard\WizardPluginBase */
  public function testCreateWorkspaceView() {
    $wizard = \Drupal::service('plugin.manager.views.wizard')->createInstance('standard:workspace', []);
    $form = [];
    $form_state = new FormState();
    $form = $wizard->buildForm($form, $form_state);
    $random_id = strtolower($this->randomMachineName());
    $random_label = $this->randomMachineName();

    $form_state->setValues([
      'id' => $random_id,
      'label' => $random_label,
      'base_table' => 'workspace',
    ]);

    $wizard->validateView($form, $form_state);
    $view = $wizard->createView($form, $form_state);
    $this->assertInstanceOf(ViewUI::class, $view);

  public function buildThemeFunctions($hook) {
    $themes = [];
    $display = isset($this->display_handler) ? $this->display_handler->display : NULL;
    $id = $this->storage->id();

    if ($display) {
      $themes[] = $hook . '__' . $id . '__' . $display['id'];
      $themes[] = $hook . '__' . $display['id'];
      // Add theme suggestions for each single tag.       foreach (Tags::explode($this->storage->get('tag')) as $tag) {
        $themes[] = $hook . '__' . preg_replace('/[^a-z0-9]/', '_', strtolower($tag));
      }

      if ($display['id'] != $display['display_plugin']) {
        $themes[] = $hook . '__' . $id . '__' . $display['display_plugin'];
        $themes[] = $hook . '__' . $display['display_plugin'];
      }
    }
    $themes[] = $hook . '__' . $id;
    $themes[] = $hook;

    return $themes;
  }

    public function makeId($callback, array $args = array())
    {
        if (!is_callable($callback, true, $name)) {
            Zend_Cache::throwException('Invalid callback');
        }

        // functions, methods and classnames are case-insensitive         $name = strtolower($name);

        // generate a unique id for object callbacks         if (is_object($callback)) { // Closures & __invoke             $object = $callback;
        } elseif (isset($callback[0])) { // array($object, 'method')             $object = $callback[0];
        }
        if (isset($object)) {
            try {
                $tmp = @serialize($callback);
            } catch (Exception $e) {

if ($this->namespaces) {
                if (isset($this->ignoredAnnotationNames[$name])) {
                    return false;
                }
                foreach ($this->namespaces as $namespace) {
                    if ($this->classExists($namespace.'\\'.$name)) {
                        $name = $namespace.'\\'.$name;
                        $found = true;
                        break;
                    }
                }
            } elseif (isset($this->imports[$loweredAlias = strtolower($alias)])) {
                $found = true;
                $name  = (false !== $pos)
                    ? $this->imports[$loweredAlias] . substr($name, $pos)
                    : $this->imports[$loweredAlias];
            } elseif ( ! isset($this->ignoredAnnotationNames[$name])
                && isset($this->imports['__NAMESPACE__'])
                && $this->classExists($this->imports['__NAMESPACE__'] . '\\' . $name)
            ) {
                $name  = $this->imports['__NAMESPACE__'].'\\'.$name;
                $found = true;
            } elseif (! isset($this->ignoredAnnotationNames[$name]) && $this->classExists($name)) {

    public static function camelize(string $id): string
    {
        return strtr(ucwords(strtr($id, ['_' => ' ', '.' => '_ ', '\\' => '_ '])), [' ' => '']);
    }

    /** * A string to underscore. */
    public static function underscore(string $id): string
    {
        return strtolower(preg_replace(['/([A-Z]+)([A-Z][a-z])/', '/([a-z\d])([A-Z])/'], ['\\1_\\2', '\\1_\\2'], str_replace('_', '.', $id)));
    }

    /** * Creates a service by requiring its factory file. * * @return mixed */
    protected function load(string $file)
    {
        return require $file;
    }

else {
                $parsed_url['host'] = $parsed_args['headers']['host'];
            }
            unset( $parsed_args['headers']['Host'], $parsed_args['headers']['host'] );
        }

        /* * Certain versions of PHP have issues with 'localhost' and IPv6, It attempts to connect * to ::1, which fails when the server is not set up for it. For compatibility, always * connect to the IPv4 address. */
        if ( 'localhost' === strtolower( $connect_host ) ) {
            $connect_host = '127.0.0.1';
        }

        $connect_host = $secure_transport ? 'ssl://' . $connect_host : 'tcp://' . $connect_host;

        $is_local   = isset( $parsed_args['local'] ) && $parsed_args['local'];
        $ssl_verify = isset( $parsed_args['sslverify'] ) && $parsed_args['sslverify'];

        if ( $is_local ) {
            /** * Filters whether SSL should be verified for local HTTP API requests. * * @since 2.8.0 * @since 5.1.0 The `$url` parameter was added. * * @param bool|string $ssl_verify Boolean to control whether to verify the SSL connection * or path to an SSL certificate. * @param string $url The request URL. */

    private function _startElement($file, $name, $attrib)
    {
        if ($this->_term !== null) {
            $this->_content .= "<".$name;
            foreach($attrib as $key => $value) {
                $this->_content .= " $key=\"$value\"";
            }
            $this->_content .= ">";
        } else {
            switch(strtolower($name)) {
                case 'termentry':
                    $this->_termentry = null;
                    break;
                case 'langset':
                    if (isset($attrib['xml:lang']) === true) {
                        $this->_langset = $attrib['xml:lang'];
                        if (isset($this->_data[$this->_langset]) === false) {
                            $this->_data[$this->_langset] = array();
                        }
                    }
                    break;

'hostname' => isset($dsn['host']) ? rawurldecode($dsn['host']) : '',
            'port'     => isset($dsn['port']) ? rawurldecode((string) $dsn['port']) : '',
            'username' => isset($dsn['user']) ? rawurldecode($dsn['user']) : '',
            'password' => isset($dsn['pass']) ? rawurldecode($dsn['pass']) : '',
            'database' => isset($dsn['path']) ? rawurldecode(substr($dsn['path'], 1)) : '',
        ];

        if (! empty($dsn['query'])) {
            parse_str($dsn['query'], $extra);

            foreach ($extra as $key => $val) {
                if (is_string($val) && in_array(strtolower($val), ['true', 'false', 'null'], true)) {
                    $val = $val === 'null' ? null : filter_var($val, FILTER_VALIDATE_BOOLEAN);
                }

                $dsnParams[$key] = $val;
            }
        }

        return array_merge($params, $dsnParams);
    }

    /** * Creates a database object. * * @param string $driver Driver name. FQCN can be used. * @param string $class 'Connection'|'Forge'|'Utils' * @param array|object $argument The constructor parameter. * * @return BaseConnection|BaseUtils|Forge */