soundex

    (PHP 4, PHP 5, PHP 7, PHP 8)

    soundex — Calculate the soundex key of a string

    Description

    soundex(string$string): string

    Calculates the soundex key of string.

    Soundex keys have the property that words pronounced similarly produce the same soundex key, and can thus be used to simplify searches in databases where you know the pronunciation but not the spelling.

    This particular soundex function is one described by Donald Knuth in "The Art Of Computer Programming, vol. 3: Sorting And Searching", Addison-Wesley (1973), pp. 391-392.

    Parameters

    string

    The input string.

    Return Values

    Returns the soundex key as a string with four characters. If at least one letter is contained in string, the returned string starts with a letter. Otherwise "0000" is returned.

    Changelog

    VersionDescription
    8.0.0 Prior to this version, calling the function with an empty string returned false for no particular reason.

    Examples

    Example #1 Soundex Examples

    <?php
    soundex    ("Euler") == soundex("Ellery"); // E460
    soundex("Gauss") == soundex("Ghosh"); // G200
    soundex("Hilbert") == soundex("Heilbronn"); // H416
    soundex("Knuth") == soundex("Kant"); // K530
    soundex("Lloyd") == soundex("Ladd"); // L300
    soundex("Lukasiewicz") == soundex("Lissajous"); // L222
    ?>

    See Also

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