ltrim - PHP code example

Make Your Code Cleaner and More Concise With the PHP Function Ltrim

The php function ltrim is a built-in string trimmer that removes white space and pre-defined characters from both sides of a given string. It accepts one mandatory parameter and an optional list of characters to be removed from the left side. The function returns the modified string.

The trim function is commonly used when there are many blank spaces at the beginning of an input string, for example, a URL or a name. However, the problem with this approach is that it also cuts off any characters within the string itself, such as spaces and tabs, and the result would be a completely different text than the original input string. This is why you should always be aware of the consequences of using this function.

Thankfully, there is a better way to handle this problem. The trim function has a similar alternative known as rtrim, which does exactly the opposite of ltrim, by trimming any white space or pre-defined characters from the end of the string.

Learn how to make your code cleaner and more concise with php function ltrim and other powerful functions. Get access to exclusive videos, interactive demos, and hands-on projects. Get now with O'Reilly Learn.

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ltrim example

    public static function get_relative_luminance_from_hex( $hex ) {

        // Remove the "#" symbol from the beginning of the color.         $hex = ltrim( $hex, '#' );

        // Make sure there are 6 digits for the below calculations.         if ( 3 === strlen( $hex ) ) {
            $hex = substr( $hex, 0, 1 ) . substr( $hex, 0, 1 ) . substr( $hex, 1, 1 ) . substr( $hex, 1, 1 ) . substr( $hex, 2, 1 ) . substr( $hex, 2, 1 );
        }

        // Get red, green, blue.         $red   = hexdec( substr( $hex, 0, 2 ) );
        $green = hexdec( substr( $hex, 2, 2 ) );
        $blue  = hexdec( substr( $hex, 4, 2 ) );

    private function do_overwrite() {
        if ( 'upload' !== $this->type || ! is_wp_error( $this->result ) || 'folder_exists' !== $this->result->get_error_code() ) {
            return false;
        }

        $folder = $this->result->get_error_data( 'folder_exists' );
        $folder = ltrim( substr( $folder, strlen( WP_PLUGIN_DIR ) ), '/' );

        $current_plugin_data = false;
        $all_plugins         = get_plugins();

        foreach ( $all_plugins as $plugin => $plugin_data ) {
            if ( strrpos( $plugin, $folder ) !== 0 ) {
                continue;
            }

            $current_plugin_data = $plugin_data;
        }

/** * @internal */
class PrefixVersionStrategyTest extends TestCase
{
    /** * @dataProvider dataProvider */
    public function testPathGetsPrefixed(string $prefix, string $fileName, string $returnPath, string $expected): void
    {
        $orgVersion = $this->createMock(FlysystemLastModifiedVersionStrategy::class);
        $orgVersion->method('applyVersion')->with(rtrim($prefix, '/') . '/' . ltrim($fileName, '/'))->willReturn($returnPath);

        $prefixVersion = new PrefixVersionStrategy(
            $prefix,
            $orgVersion
        );

        static::assertSame($expected, $prefixVersion->getVersion($fileName));
    }

    public static function dataProvider(): iterable
    {

    private function getClass(object|string $value): string
    {
        if (\is_string($value)) {
            if (!class_exists($value) && !interface_exists($value, false)) {
                throw new InvalidArgumentException(sprintf('The class or interface "%s" does not exist.', $value));
            }

            return ltrim($value, '\\');
        }

        return $value::class;
    }
}

$original_begin    = "\n" === substr( $original, 0, 1 );
            $original_end      = "\n" === substr( $original, -1 );
            $translation_begin = "\n" === substr( $translation, 0, 1 );
            $translation_end   = "\n" === substr( $translation, -1 );

            if ( $original_begin ) {
                if ( ! $translation_begin ) {
                    $translation = "\n" . $translation;
                }
            } elseif ( $translation_begin ) {
                $translation = ltrim( $translation, "\n" );
            }

            if ( $original_end ) {
                if ( ! $translation_end ) {
                    $translation .= "\n";
                }
            } elseif ( $translation_end ) {
                $translation = rtrim( $translation, "\n" );
            }

            return $translation;
        }

// We have already included this in the previous                     // iteration, so reset this flag                     $optionValue = false;
                } else {
                    // Yup, it's a segment                     static::$segments[] = $arg;
                }

                continue;
            }

            $arg   = ltrim($arg, '-');
            $value = null;

            if (isset($args[$i + 1]) && mb_strpos($args[$i + 1], '-') !== 0) {
                $value       = $args[$i + 1];
                $optionValue = true;
            }

            static::$options[$arg] = $value;
        }
    }

        return ($this->lazyObjectState->realInstance ??= ($this->lazyObjectState->initializer)())->lrange(...\func_get_args());
    }

    public function lrem($key, $value, $count)
    {
        return ($this->lazyObjectState->realInstance ??= ($this->lazyObjectState->initializer)())->lrem(...\func_get_args());
    }

    public function ltrim($key, $start, $stop)
    {
        return ($this->lazyObjectState->realInstance ??= ($this->lazyObjectState->initializer)())->ltrim(...\func_get_args());
    }

    public function mget($keys)
    {
        return ($this->lazyObjectState->realInstance ??= ($this->lazyObjectState->initializer)())->mget(...\func_get_args());
    }

    public function migrate($host, $port, $key, $db, $timeout, $copy = null, $replace = null)
    {
        return ($this->lazyObjectState->realInstance ??= ($this->lazyObjectState->initializer)())->migrate(...\func_get_args());
    }

    /** * @return $this */
    public function setPath(string $pattern): static
    {
        $pattern = $this->extractInlineDefaultsAndRequirements($pattern);

        // A pattern must start with a slash and must not have multiple slashes at the beginning because the         // generated path for this route would be confused with a network path, e.g. '//domain.com/path'.         $this->path = '/'.ltrim(trim($pattern), '/');
        $this->compiled = null;

        return $this;
    }

    public function getHost(): string
    {
        return $this->host;
    }

    /** * @return $this */

        // without leading slash, detail would be stripped         $baseUrl = rtrim($baseUrl, '/') . '/';

        if ($this->equalsBaseUrl($seoPathInfo, $baseUrl)) {
            $seoPathInfo = '';
        } elseif ($this->containsBaseUrl($seoPathInfo, $baseUrl)) {
            $seoPathInfo = mb_substr($seoPathInfo, mb_strlen($baseUrl));
        }

        $resolved = $this->resolver->resolve($languageId, $salesChannelId, $seoPathInfo);

        $resolved['pathInfo'] = '/' . ltrim($resolved['pathInfo'], '/');

        return $resolved;
    }

    private function getSchemeAndHttpHost(Request $request): string
    {
        return $request->getScheme() . '://' . idn_to_utf8($request->getHttpHost());
    }

    /** * We add the trailing slash to the base url * so we have to add it to the path info too, to check if they are equal */

/** * Returns the headers without consuming the response. */
    public function getHeaders(): array
    {
        $headers = [];

        foreach ($this->response->getInfo('response_headers') as $h) {
            if (11 <= \strlen($h) && '/' === $h[4] && preg_match('#^HTTP/\d+(?:\.\d+)? ([123456789]\d\d)(?: |$)#', $h, $m)) {
                $headers = [];
            } elseif (2 === \count($m = explode(':', $h, 2))) {
                $headers[strtolower($m[0])][] = ltrim($m[1]);
            }
        }

        return $headers;
    }

    /** * @return resource|null The PHP stream resource where the content is buffered, if it is */
    public function getContent()
    {

if (null !== $exists = &self::$existsCache[$this->resource]) {
            if ($loaded) {
                $exists = [true, null];
            } elseif (0 >= $timestamp && !$exists[0] && null !== $exists[1]) {
                throw new \ReflectionException($exists[1]);
            }
        } elseif ([false, null] === $exists = [$loaded, null]) {
            if (!self::$autoloadLevel++) {
                spl_autoload_register(__CLASS__.'::throwOnRequiredClass');
            }
            $autoloadedClass = self::$autoloadedClass;
            self::$autoloadedClass = ltrim($this->resource, '\\');

            try {
                $exists[0] = class_exists($this->resource) || interface_exists($this->resource, false) || trait_exists($this->resource, false);
            } catch (\Exception $e) {
                $exists[1] = $e->getMessage();

                try {
                    self::throwOnRequiredClass($this->resource, $e);
                } catch (\ReflectionException $e) {
                    if (0 >= $timestamp) {
                        throw $e;
                    }

$admin_body_classes = apply_filters( 'admin_body_class', '' );
$admin_body_classes = ltrim( $admin_body_classes . ' ' . $admin_body_class );
?> <body class="wp-admin wp-core-ui no-js <?php echo esc_attr( $admin_body_classes ); ?>"> <script type="text/javascript"> document.body.className = document.body.className.replace('no-js','js'); </script> <?php // Make sure the customize body classes are correct as early as possible. if ( current_user_can( 'customize' ) ) {
wp_customize_support_script();
}

        if ($this->const) {
            $out .= ' const';
        }

        if ($this->static) {
            $out .= ' static';
        }

        if (null !== $out && \strlen($out)) {
            return \ltrim($out);
        }

        return null;
    }

    public function getAccess(): ?string
    {
        switch ($this->access) {
            case self::ACCESS_PRIVATE:
                return 'private';
            case self::ACCESS_PROTECTED:

$parts = explode('\\', $class);
        $short = array_pop($parts);

        return sprintf('<abbr title="%s">%s</abbr>', $class, $short);
    }

    private function getFileRelative(string $file): ?string
    {
        $file = str_replace('\\', '/', $file);

        if (null !== $this->projectDir && str_starts_with($file, $this->projectDir)) {
            return ltrim(substr($file, \strlen($this->projectDir)), '/');
        }

        return null;
    }

    private function getFileLink(string $file, int $line): string|false
    {
        if ($fmt = $this->fileLinkFormat) {
            return \is_string($fmt) ? strtr($fmt, ['%f' => $file, '%l' => $line]) : $fmt->format($file, $line);
        }

            } elseif (!\function_exists('iconv')) {
                $s = preg_replace('/[^\x00-\x7F]/u', '?', $s);
            } else {
                $s = @preg_replace_callback('/[^\x00-\x7F]/u', static function D$c) {
                    $c = (string) iconv('UTF-8', 'ASCII//TRANSLIT', $c[0]);

                    if ('' === $c && '' === iconv('UTF-8', 'ASCII//TRANSLIT', '²')) {
                        throw new \LogicException(sprintf('"%s" requires a translit-able iconv implementation, try installing "gnu-libiconv" if you\'re using Alpine Linux.', static::class));
                    }

                    return 1 < \strlen($c) ? ltrim($c, '\'`"^~') : ('' !== $c ? $c : '?');
                }, $s);
            }
        }

        $str->string .= $s;

        return $str;
    }

    public function camel(): static
    {