Re: [PHP] PCRE false match with preg_match?
Murray @ PlanetThoughtful wrote: > Changing the "*" to a "+" (at least one or more occurrences) could 'fix' > that pattern (ie so that it doesn't match your string), depending on any > other values being tested by it. *keyboardbiting* I see... thanks to all of you who helped so fast. Jens -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PCRE false match with preg_match?
Murray: I could kick myself for not seeing that one (* = 0 or more, well it sure found 0) On 9/26/05, Murray @ PlanetThoughtful <[EMAIL PROTECTED]> wrote: > > I recently encountered a strange behaviour, could someone please > > countercheck it, to either tell me there is an error in my pattern? > > > > I have a test string: "7005-N/52" > > I have two match patterns:a) "/([0-9]*)\/(.*)/i" > > b) "/([0-9]*)\-(.*)/i" > > I check the test string with the help of preg_match, and they both > > matched, but normally variant a) shouldn't have matched. > > > > Normally I test my patterns with the tool "The Regex Coach", and > > according to this tool it shouldn't have matched. > > PHP version is 5.0.4, PCRE extension version is 4.5 01-December-2003 > > Hi Jens > > Your first pattern 'matches' because it finds a hit on the "/52" component > of your test string. > > If you look at the pattern itself, it's because you're using the > 'zero-or-more-occurrences' quantifier (ie "*") in the first part of your > pattern: "([0-9]*)". > > It's a valid hit, because there are zero incidences of numeric characters > immediately prior to the "/52" component of the test string. > > Changing the "*" to a "+" (at least one or more occurrences) could 'fix' > that pattern (ie so that it doesn't match your string), depending on any > other values being tested by it. > > Much warmth, > > Murray > --- > "Lost in thought..." > http://www.planetthoughtful.org > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] PCRE false match with preg_match?
> I recently encountered a strange behaviour, could someone please > countercheck it, to either tell me there is an error in my pattern? > > I have a test string: "7005-N/52" > I have two match patterns:a) "/([0-9]*)\/(.*)/i" > b) "/([0-9]*)\-(.*)/i" > I check the test string with the help of preg_match, and they both > matched, but normally variant a) shouldn't have matched. > > Normally I test my patterns with the tool "The Regex Coach", and > according to this tool it shouldn't have matched. > PHP version is 5.0.4, PCRE extension version is 4.5 01-December-2003 Hi Jens Your first pattern 'matches' because it finds a hit on the "/52" component of your test string. If you look at the pattern itself, it's because you're using the 'zero-or-more-occurrences' quantifier (ie "*") in the first part of your pattern: "([0-9]*)". It's a valid hit, because there are zero incidences of numeric characters immediately prior to the "/52" component of the test string. Changing the "*" to a "+" (at least one or more occurrences) could 'fix' that pattern (ie so that it doesn't match your string), depending on any other values being tested by it. Much warmth, Murray --- "Lost in thought..." http://www.planetthoughtful.org -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] PCRE false match with preg_match?
Jake was fast ;-) and he is on the right track too
(although I don't think that the substrings he guessed are
the exact ones that are found).
you might want to check preg_match_all to see the matches
that PCRE comes up with for each regexp...
also take a look at:
$test = "7005-N/52";
var_dump(
preg_match("/([0-9]*)\/(.*)/i", $test),
preg_match("/([0-9]*)\-(.*)/i", $test),
preg_match("/^([0-9]*)\/(.*)$/i", $test),
preg_match("/^([0-9]*)\-(.*)$/i", $test)
);
Jake Gardner wrote:
When using "/([0-9]*)(.*)/i" it matches
substring 1: 7005
substring 2: -N/52
When using "/([0-9]*)\/(.*)/i" it matches
substring 1:
substring 2: 52
It looks to me as though its trying to match either or subgroup in order.
On 9/26/05, Jens Schulze <[EMAIL PROTECTED]> wrote:
I recently encountered a strange behaviour, could someone please
countercheck it, to either tell me there is an error in my pattern?
I have a test string: "7005-N/52"
I have two match patterns: a) "/([0-9]*)\/(.*)/i"
b) "/([0-9]*)\-(.*)/i"
I check the test string with the help of preg_match, and they both
matched, but normally variant a) shouldn't have matched.
Normally I test my patterns with the tool "The Regex Coach", and
according to this tool it shouldn't have matched.
PHP version is 5.0.4, PCRE extension version is 4.5 01-December-2003
Thanks for any help or feedback,
Jens
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Re: [PHP] PCRE false match with preg_match?
When using "/([0-9]*)(.*)/i" it matches substring 1: 7005 substring 2: -N/52 When using "/([0-9]*)\/(.*)/i" it matches substring 1: substring 2: 52 It looks to me as though its trying to match either or subgroup in order. On 9/26/05, Jens Schulze <[EMAIL PROTECTED]> wrote: > I recently encountered a strange behaviour, could someone please > countercheck it, to either tell me there is an error in my pattern? > > I have a test string: "7005-N/52" > I have two match patterns: a) "/([0-9]*)\/(.*)/i" >b) "/([0-9]*)\-(.*)/i" > I check the test string with the help of preg_match, and they both > matched, but normally variant a) shouldn't have matched. > > Normally I test my patterns with the tool "The Regex Coach", and > according to this tool it shouldn't have matched. > PHP version is 5.0.4, PCRE extension version is 4.5 01-December-2003 > > Thanks for any help or feedback, > Jens > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
