Help with regular expression

[Tony Marston]

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the separator
is enclosed in parentheses. For example, take the string "field1,
CONCAT(field2,' ', field3) as field23, field4". I would like to be able to
split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Thanks in advance.

--
Tony Marston
http://www.tonymarston.net

[Pedro Graca]

Tony Marston wrote:

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the separator
is enclosed in parentheses. For example, take the string "field1,
CONCAT(field2,' ', field3) as field23, field4". I would like to be able to
split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Can it happen that you will have nested parenthesis? :-)
Would you consider dumping preg_* function and parsing the string?

<?php
function parse_split_comma_ignore_paren($text) {
$retval = array();
$paren = 0;
$last_index = 0;
for ($index = 0; $index < strlen($text); ++$index) {
if ($text{$index} == '(') {++$paren; continue;}
/* assumes $paren will never be negative */
if ($text{$index} == ')') {--$paren; continue;}
if ($paren) continue;
if ($text{$index} == ',') {
$retval[] = trim(substr($text, $last_index, $index-$last_index));
$last_index = $index + 1;
}
}
$retval[] = trim(substr($text, $last_index));
return $retval;
}

$s = 'field1, CONCAT(field2, \' \', field3) as field23, field4,1,,3,4';

$parts = parse_split_comma_ignore_paren($s);
print_r($parts);
?>

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[Chung Leong]

Tony Marston wrote:

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the separator
is enclosed in parentheses. For example, take the string "field1,
CONCAT(field2,' ', field3) as field23, field4". I would like to be able to
split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Thanks in advance.

--
Tony Marston
http://www.tonymarston.net

This works for the text format you described. Doesn't work in
situations where you might have paraphrases inside literal strings. For
that you'd need a solution like that one Pedro suggested.

preg_match_all('/\s*([^,]*\(.+[^\)]\)[^,]*|[^,]+)\s*/', $text, $m);
$list = $m[1];

[Jim Michaels]

([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+)|,([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+){1,}

the problem with doing this is that you are going to get CONCAT AS (...) as
one of your array elements, so just delete it or detect and ignore it.
you can always detect it with preg_match("/^CONCAT/",$string);
"Tony Marston" <to**@NOSPAM.demon.co.uk> wrote in message
news:dq*******************@news.demon.co.uk...

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the
separator is enclosed in parentheses. For example, take the string "field1,
CONCAT(field2,' ', field3) as field23, field4". I would like to be able to
split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Thanks in advance.

--
Tony Marston
http://www.tonymarston.net

[Jim Michaels]

"Jim Michaels" <jm******@nospam.yahoo.com> wrote in message
news:lO********************@comcast.com...

([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+)|,([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+){1,}
try this one. you might get better results. the ?;, may need to be changed
to (, instead for things to work.
(?:[cC][oO][nN][cC][aA][tT]\s\(?:.*\)\s[aA][sS])?\s*(\w+\d+)(?:,(?:[cC][oO][nN][cC][aA][tT]\s\(?:.*\)\s[aA][sS])?\s*(\w+\d+)){0,}


the problem with doing this is that you are going to get CONCAT AS (...)
as one of your array elements, so just delete it or detect and ignore it.
you can always detect it with preg_match("/^CONCAT/",$string);
"Tony Marston" <to**@NOSPAM.demon.co.uk> wrote in message
news:dq*******************@news.demon.co.uk...

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the
separator is enclosed in parentheses. For example, take the string
"field1, CONCAT(field2,' ', field3) as field23, field4". I would like to
be able to split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Thanks in advance.

--
Tony Marston
http://www.tonymarston.net

[Jim Michaels]

"Jim Michaels" <jm******@nospam.yahoo.com> wrote in message
news:K_********************@comcast.com...

"Jim Michaels" <jm******@nospam.yahoo.com> wrote in message
news:lO********************@comcast.com...

([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+)|,([cC][oO][nN][cC][aA][tT]\s\(.*\)\s[aA][sS])?\s*(\w+\d+){1,}
try this one. you might get better results. the ?;, may need to be changed
to (, instead for things to work.
(?:[cC][oO][nN][cC][aA][tT]\s\(?:.*\)\s[aA][sS])?\s*(\w+\d+)(?:,(?:[cC][oO][nN][cC][aA][tT]\s\(?:.*\)\s[aA][sS])?\s*(\w+\d+)){0,}

I forgot to mention - this must be used with the preg_match series of
functions, not ereg series.

the problem with doing this is that you are going to get CONCAT AS (...)
as one of your array elements, so just delete it or detect and ignore it.
you can always detect it with preg_match("/^CONCAT/",$string);
"Tony Marston" <to**@NOSPAM.demon.co.uk> wrote in message
news:dq*******************@news.demon.co.uk...

I am seeking help with a regular expression that will split a string into
several parts with ',' (comma) as the separator, but NOT where the
separator is enclosed in parentheses. For example, take the string
"field1, CONCAT(field2,' ', field3) as field23, field4". I would like to
be able to split this into the following:
[0] field1
[1] CONCAT(field2,' ', field3) as field23
[2] field4

Thanks in advance.

--
Tony Marston
http://www.tonymarston.net