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How can I make these html & php patterns work?

I am trying to make an input with regex for the following pattern:

  • Force start first character with a capital letter
  • Force first character of other WORDS (letters) capital letter
  • Force all other letters in words lowercase
  • Allow numbers & special characters anywhere except 1st character of words
<input type="text" name="display_name" placeholder="Display Name" id="display_name" required minlength="1" maxlength="32" 
pattern="[A-Z].{1,1}[a-z1-9W_]).{,}[ ]{,}[A-Z].{1,1}[a-z1-9W_]).{,}[ ]{,}[A-Z].{1,1}[a-z1-9W_]).{,}[ ]{,}">

Also, if you can do this pattern, can I also get the same pattern to use for php pregreplace.

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2

Answers


  1. 0

    As pointed out in the comments, the older regex has some problems. So, you can try this new regex.

    /^[A-Z](?:[a-z0-9W_]+)(?:s+[A-Z](?:[a-z0-9W_]+(?=[A-Z]|s|$))*)$/

    This is a fiddle showing some test cases.

    And here is the PHP in which this regex can be used.

    $input = "YourInputStringHere";

$pattern = '/^[A-Z](?:[a-z0-9W_]+)(?:s+[A-Z](?:[a-z0-9W_]+(?=[A-Z]|s|$))*)$/';

if (preg_match($pattern, $input)) {
    echo "Valid input!";
} else {
    echo "Invalid input!";
}

    And if you want to convert this into function, then try following:

    function isValidName($name) {
    if ($name !== null && $name !== '') {
        $pattern = '/^[A-Z](?:[a-z0-9W_]+)(?:s+[A-Z](?:[a-z0-9W_]+(?=[A-Z]|s|$))*)$/';
        return preg_match($pattern, $name);
    }
    return false;
}

    And, if you want to use Javascript to force the input to follow the regex, you can try the following:

    document.getElementById('display_name').addEventListener('input', function() {
    const pattern = /^[A-Z](?:[a-z0-9W_]+)(?:s+[A-Z](?:[a-z0-9W_]+(?=[A-Z]|s|$))*)$/;
    const displayName = this.value;
    const errorMessage = document.getElementById('error_message'); // This is just for the sake of error showing, you can remove it.

    if (!pattern.test(displayName)) {
        // The entered displayName is invalid, showing error. You can change it according to your needs.
        errorMessage.textContent = "Invalid pattern. Please follow the format: Each word starts with a capital letter.";
    } else {
        // Clearing any previously shown errors.
        errorMessage.textContent = "";
    }
});

    And the error_message is just a span. Also, after this Javascript, I don’t think you would need the pattern thing in your input. So, if you are using this Javascript, you can remove the pattern from your input.

    Hope this helps.

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  2. 0

    When using PHP, you could use:

    ^[A-Z][^A-Zs]*(?:h+[A-Z][^A-Zs]*)*$

    The regex in parts matches:

    • ^ Start of string
    • [A-Z] Match an uppercase char A-Z
    • [^A-Zs]* Match 0+ times any character except an uppercase char A-Z or a whitespace char
    • (?: Non capture group to repeat as a whole part
      • h+ Match 1+ horizontal whitespace chars
      • [A-Z][^A-Zs]* Match a char A-Z and 0+ times any character except an uppercase char A-Z or a whitespace char
    • )* Close the non capture group and optionally repeat
    • $ End of string

    See a regex demo.

    For Javascript you could slightly change the regex to:

    ^[A-Z][^A-Zs]*(?:[^Sn]+[A-Z][^A-Zs]*)*$

    See another regex demo

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