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If I put * in my regex, it doesn't work, if I put +, it works.
* should mean 0 or more, + should mean 1 or more.
Case with *
$num = ' 527545855 ';
var_dump( preg_match( '/\d*/', substr( $num, 0, 18 ), $coincidencias ) );
var_dump($coincidencias);exit;
Result:
int(1)
array(1) {
[0]=>
string(0) ""
}
Case with +
$num = ' 527545855 ';
var_dump( preg_match( '/\d+/', substr( $num, 0, 18 ), $coincidencias ) );
var_dump($coincidencias);exit;
Result:
int(1)
array(1) {
[0]=>
string(9) "527545855"
}
I thought both should work, but I don't understand why the * doesn't work.
396
* means zero-or-more, and + means one-or-more. So the difference is that the empty string would match the second expression but not the first.
In regex, the uppercase metacharacter denotes the inverse of the lowercase counterpart, for example, \w for word character and \W for non-word character; \d for digit and \D or non-digit.
Example: "a\+" matches "a+" and not a series of one or "a"s. ^ the caret is the anchor for the start of the string, or the negation symbol. Example: "^a" matches "a" at the start of the string. Example: "[^0-9]" matches any non digit.
\n. Matches a newline character. \r. Matches a carriage return character.
* means 0 or more occurences thus the first occurence is the void string in your test string
58
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