Getting the first character of a string with PHP

Published on 2021-11-12 • Modified on 2021-11-12

In this snippet, we see how to get the first character of a string with PHP and Symfony. In the first part, we see how to use the array access notation. We must be careful because it won't work with special characters. In this case, we have to use the mb_substr function. In the second part, we see how to use the Symfony string component. It automatically handles everything: special characters, empty strings and null values.

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<?php

declare(strict_types=1);

namespace App\Controller\Snippet;

use App\Helper\String\StringHelper;

use function Symfony\Component\String\u;

/**
 * I am using a PHP trait to isolate each snippet in a file.
 * This code should be called from a Symfony controller extending AbstractController (as of Symfony 4.2)
 * or Symfony\Bundle\FrameworkBundle\Controller\Controller (Symfony <= 4.1).
 * Services are injected in the main controller constructor.
 *
 * @property StringHelper $stringHelper
 */
trait Snippet173Trait
{
    public function snippet173(): void
    {
        echo "—— Array access ——————————————————————————————————————————————\n";

        $str = 'ABCD';
        echo 'Case n°1 : ';
        echo $str[0]; // A
        echo "\n";

        $str = 'äBCD';
        echo 'Case n°2 : ';
        echo $str[0]; // � => Doesn't work because ä is a special character
        echo "\n";

        echo 'Case n°3 : ';
        echo mb_substr($str, 0, 1); // ä => OK using mb_substr with a special character
        echo "\n";

        $str = '';
        echo 'Case n°4 : ';
        echo @$str[0]; // PHP Warning. PHPStan error: Offset 0 does not exist on ''. @phpstan-ignore-line
        echo "\n";

        $str = null;
        echo 'Case n°5 : ';
        echo @$str[0]; //  PHP Warning. PHPStan error: Offset 0 does not exist on null. @phpstan-ignore-line
        echo "\n";

        echo "\n";
        echo "—— With the Symfony string component —————————————————————————\n";

        $str = u('ABCD');
        echo 'Case n°6 : ';
        echo $str->slice(0, 1); // A
        echo "\n";

        $str = u('äBCD');
        echo 'Case n°7 : ';
        echo $str->slice(0, 1); // ä => The Symfony component automatically hanldes special characters
        echo "\n";

        $str = u('');
        echo 'Case n°8 : ';
        echo $str->slice(0, 1); // "" => returns an empty string in this case
        echo "\n";

        $str = u(null);
        echo 'Case n°9 : ';
        echo $str->slice(0, 1); // "" => also returns an empty string in this case

        echo "\n\n";
        echo "—— With my Symfony string component helper ———————————————————\n";

        echo 'Case n°10 : ';
        echo $this->stringHelper->u('ABCD')->firstChar(); // "A"
        echo "\n";

        echo 'Case n°11 : ';
        echo $this->stringHelper->u('äBCD')->firstChar(); // "ä"
        echo "\n";

        echo 'Case n°12 : ';
        echo $this->stringHelper->u('')->firstChar(); // ""
        echo "\n";

        echo 'Case n°13 : ';
        echo $this->stringHelper->u(null)->firstChar(); // ""

        // this firstChar() function is a custom function I have added (blog post to come)

        // That's it! 😁
    }
}

 Run this snippet  ≪ this.showUnitTest ? this.trans.hide_unit_test : this.trans.show_unit_test ≫  More on Stackoverflow   Read the doc  More on the web

  Work with me!

<?php

declare(strict_types=1);

namespace App\Tests\Integration\Controller\Snippets;

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

use function Symfony\Component\String\u;

/**
 * @see Snippet173Trait
 */
final class Snippet173Test extends KernelTestCase
{
    /**
     * @see Snippet173Trait::snippet173
     */
    public function testSnippet173(): void
    {
        $str = 'ABCD';
        self::assertSame('A', $str[0]);

        $str = 'äBCD';
        self::assertNotSame('ä', $str[0]);

        $str = 'äBCD';
        self::assertSame('ä', mb_substr($str, 0, 1));

        $str = u('ABCD');
        self::assertSame('A', $str->slice(0, 1)->toString());

        $str = u('äBCD');
        self::assertSame('ä', $str->slice(0, 1)->toString());

        $str = u('');
        self::assertSame('', $str->slice(0, 1)->toString());

        $str = u(null);
        self::assertSame('', $str->slice(0, 1)->toString());
    }
}

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