CODEWITHSUNDEEP
phpregex
Jeffrey
Jeffrey

Reputation: 1804

regex doesn't work for empty strings

I would like to get the content in between of a single string, however, if the content is empty, my regex is failing...

<?PHP
$string = "
blaat = 'Some string with an escaped \' quote'; // some comment.
empty1 = ''; // omg! an empty string!
empty2 = ''; // omg! an empty string!
";

preg_match_all( '/(?<not>\'.*?[^\\\]\')/ims', $string, $match );

echo '<pre>';
print_r( $match['not'] );
echo '</pre>';
?>

This will give as output:

Array
(
    [0] => 'Some string with an escaped \' quote'
    [1] => ''; // omg! an empty string!
empty2 = '
)

I know this problem can be fixed with the following regex, thought i'm looking for a true solution in stead of a fix for every exception...

preg_match_all( '/((\'\')|(?<not>\'(.*?[^\\\])?\'))/ims', $string, $match );

Upvotes: 1

Views: 155

Answers (2)

greg
greg

Reputation: 3495

<?php
$string = "
blaat = 'Some string with an escaped \' quote'; // some comment.
empty1 = ''; // omg! an empty string!
empty2 = ''; // omg! an empty string!
not_empty = 'Another non empty with \' quote'; 

";

$parts = preg_split("/[^']*'(.*)'.*|[^']+/", $string, 0, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);

print_r($parts);

will output

Array
(
    [0] => Some string with an escaped \' quote
    [1] => Another non empty with \' quote
)

Upvotes: 1

kevinAlbs
kevinAlbs

Reputation: 1124

<?PHP
$string = "
blaat = 'Some string with an escaped \' quote'; // some comment.
empty1 = ''; // omg! an empty string!
empty2 = ''; // omg! an empty string!
";

preg_match_all( '/(?<not>
    \'          #match first quote mark
    .*?         #match all characters, ungreedy
    (?<!\\\)    #use a negative lookbehind assertion
    \'
    )
/ixms', $string, $match );

echo '<pre>';
print_r( $match['not'] );
echo '</pre>';

?>

Worked for me. I also added the /x freespacing mode to space it out a bit and make it easier to read.

Upvotes: 0

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