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<h1>Regex Modifier: [123]</h1>
<p>How many characters in the text "W3Schools has been live since 1999" is either the number "1", "2", or "3":</p>
$txt = "W3Schools has been live since 1999";
$pattern = "/[123]/";
echo preg_match_all($pattern, $txt);
<p>The matches were found here:</p>
echo preg_replace($pattern, "#", $txt);
<p>(Each match was replaced by a # character)</p>
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How many characters in the text "W3Schools has been live since 1999" is either the number "1", "2", or "3":
2The matches were found here:
W#Schools has been live since #999(Each match was replaced by a # character)