I have two strings:
$relativeUrl = "/string1/(\d+)/string2/(\d+)/string3";
$currentUrl = "/string1/1234/string2/5678/string3";
I am trying to assert that the $currentUrl does indeed match $relativeUrl which contains regexes for two numbers ((\d+)). The result I want is simply a true or false value.
I have tried using preg_quote() because:
preg_quote() takes str and puts a backslash in front of every character that is part of the regular expression syntax. This is useful if you have a run-time string that you need to match in some text and the string may contain special regex characters.
However, I have to [pre|ap]pend the delimiters in order to not receive the Unknown modifier '\' error and even then, I just get an empty array back. I'm not sure how else is best to go about this.
preg_match("^" . preg_quote($relativeUrl) . "^", $currentUrl, $matches);
var_dump($matches); // Gives array(0) { }
Am I going about this the right way? How can I achieve what I require?
Try this preg_match without preg_quote:
preg_match('#' . $relativeUrl . '#', $currentUrl, $matches);
Related
I cant remember what to use to return only a specific part of a string.
I have a string like this:-
$str = "return(me or not?)";
I want to get the word which is after (. In this example me will be my result. How can I do this?
I dont think substr is what I am looking for. as substr returns value based on the index you provided. which in this case i dont know the index, it can vary. All I know is that I want to return whatever is after "(" and before the space " ". The index positions will always be different there for i cant use substr(..).
This regular expression should do the trick. Since you didn't provide general rules but only an example it might need further changes though.
preg_match('/\((\S+)/', $input, $matches);
$matches[1] contains "me" then.
<?php
// Your input string
$string = "return(me or not?)";
// Pattern explanation:
// \( -- Match opening parentheses
// ([^\s]+) -- Capture at least one character that is not whitespace.
if (preg_match('/\(([^\s]+)/', $string, $matches) === 1)
// preg_match() returns 1 on success.
echo "Substring: {$matches[1]}";
else
// No match found, or bad regular expression.
echo 'No match found';
Result of capture group will be your result using this regex and preg_match().
$regex = '/\((\w+)/';
Check preg_match() for the working reference.
Why doesn't preg_replace return anything in this scenario? I've been trying to figure it out all night.
Here is the text contained within $postContent:
Test this. Here is a quote: [Quote]1[/Quote] Quote is now over.
Here is my code:
echo "Test I'm Here!!!";
$startQuotePos = strpos($postContent,'[Quote]')+7;
$endQuotePos = strpos($postContent,'[/Quote]');
$postStrLength = strlen($postContent);
$quotePostID = substr($postContent,$startQuotePos,($endQuotePos-$postStrLength));
$quotePattern = '[Quote]'.$quotePostID.'[/Quote]';
$newPCAQ = preg_replace($quotePattern,$quotePostID,$postContent);
echo "<br />$startQuotePos<br />$endQuotePos<br />$quotePostID<br />Qpattern:$quotePattern<br />PCAQ: $newPCAQ<br />";
This is my results:
Test I'm Here!!!
35
36
1
Qpattern:[Quote]1[/Quote]
PCAQ:
For preg_replace(), "[Quote]" matches a single character that is one of the following: q, u, o, t, or e.
If you want that preg_replace() finds the literal "[Quote]", you need to escape it as "\[Quote\]". preg_quote() is the function you should use: preg_quote("[Quote]").
Your code is also wrong because a regular expression is expected to start with a delimiter. In the preg_replace() call I am showing at the end of my answer, that is #, but you could use another character, as long as it doesn't appear in the regular expression, and it is used also at the end of the regular expression. (In my case, # is followed by a pattern modifier, and pattern modifiers are the only characters allowed after the pattern delimiter.)
If you are going to use preg_replace(), it doesn't make sense that you first find where "[Quote]" is. I would rather use the following code:
$newPCAQ = preg_replace('#\[Quote\](.+?)\[/Quote\]#i', '\1', $postContent);
I will explain the regular expression I am using:
The final '#i' is saying to preg_replace() to ignore the difference between lowercase, and uppercase characters; the string could contain "[QuOte]234[/QuOTE]", and that substring would match the regular expression the same.
I use a question mark in "(.+?)" to avoid ".+" is too greedy, and matches too much characters. without it, the regular expression could include in a single match a substring like "[Quote]234[/Quote] Other text [Quote]475[/Quote]" while this should be matched as two substrings: "[Quote]234[/Quote]", and "[Quote]475[/Quote]".
The '\1' string I am using as replacement string is saying to preg_replace() to use the string matched from the sub-group "(.+?)" as replacement. In other words, the call to preg_replace() is removing "[Quote]", and "[/Quote]" surrounding other text. (It doesn't replace "[/Quote]" that doesn't match with "[Quote]", such as in "[/Quote] Other text [Quote]".)
your regex must start & end with '/':
$quotePattern = '/[Quote]'.$quotePostID.'[/Quote]/';
The reason you don't see anything for the return value of preg_replace is because it has returned NULL (see the manual link for details). This is what preg_replace returns when an error occurs, which is what happened in your situation. The string value of NULL is a zero-length string. You can see this by using var_dump instead, which will tell you that preg_replace returned NULL.
Your regular expression is invalid and as such PHP will throw an E_WARNING level error of Warning: preg_replace(): Unknown modifier '['
There are a couple of reason for this. First, you need to specify an opening and closing delimiter for you regular expression as preg_* functions use PCRE style regular expression. Second, you want to also consider using preg_quote on your patter (sans the delimiter) to ensure it is escaped properly.
$postContent = "Test this. Here is a quote: [Quote]1[/Quote] Quote is now over.";
/* Specify a delimiter for your regular expression */
$delimiter = '#';
$startQuotePos = strpos($postContent,'[Quote]')+7;
$endQuotePos = strpos($postContent,'[/Quote]');
$postStrLength = strlen($postContent);
$quotePostID = substr($postContent,$startQuotePos,($endQuotePos-$postStrLength));
/* Make sure you use the delimiter in your pattern and escape it properly */
$quotePattern = $delimiter . preg_quote("[Quote]{$quotePostID}[/Quote]", $delimiter) . $delimiter;
$newPCAQ = preg_replace($quotePattern,$quotePostID,$postContent);
echo "<br />$startQuotePos<br />$endQuotePos<br />$quotePostID<br />Qpattern:$quotePattern<br />PCAQ: $newPCAQ<br />";
The output will be:
35
36
1
Qpattern:#[Quote]1[/Quote]#
PCAQ: Test this. Here is a quote: 1 Quote is now over.
I got the following URL
http://www.amazon.com/LEGO-Ultimate-Building-Set-Pieces/dp/B000NO9GT4/ref=sr_1_1?m=ATVPDKIKX0DER&s=toys-and-games&ie=UTF8&qid=1350518571&sr=1-1&keywords=lego
and I want to extract
B000NO9GT4
that is the asin...to now, I can get search between the string, but not in this way I require. I saw the split functin, I saw the explode. but cant find a way out...also, the urls will be different in length so I cant hardcode the length two..the only thing which make some sense in my mind is to split the string so that
http://www.amazon.com/LEGO-Ultimate-Building-Set-Pieces/dp/
become first part
and
B000NO9GT4/ref=sr_1_1?m=ATVPDKIKX0DER&s=toys-and-games&ie=UTF8&qid=1350518571&sr=1-1&keywords=lego
becomes the 2nd part , from the second part , I should extract B000NO9GT4
in the same way, i would want to get product name LEGO-Ultimate-Building-Set-Pieces from the first part
I am very bad at regex and cant find a way out..
can somebody guide me how I can do it in php?
thanks
This grabs both pieces of information that you are looking to capture:
$url = 'http://www.amazon.com/LEGO-Ultimate-Building-Set-Pieces/dp/B000NO9GT4/ref=sr_1_1?m=ATVPDKIKX0DER&s=toys-and-games&ie=UTF8&qid=1350518571&sr=1-1&keywords=lego';
$path = parse_url($url, PHP_URL_PATH);
if (preg_match('#^/([^/]+)/dp/([^/]+)/#i', $path, $matches)) {
echo "Description = {$matches[1]}<br />"
."ASIN = {$matches[2]}<br />";
}
Output:
Description = LEGO-Ultimate-Building-Set-Pieces
ASIN = B000NO9GT4
Short Explanation:
Any expressions enclosed in ( ) will be saved as a capture group. This is how we get at the data in $matches[1] and $matches[2].
The expression ([^/]+) says to match all characters EXCEPT / so in effect it captures everything in the URL between the two / separators. I use this pattern twice. The [ ] actually defines the character class which was /, the ^ in this case negates it so instead of matching / it matches everything BUT /. Another example is [a-f0-9] which would say to match the characters a,b,c,d,e,f and the numbers 0,1,2,3,4,5,6,7,8,9. [^a-f0-9] would be the opposite.
# is used as the delimiter for the expression
^ following the delimiter means match from the beginning of the string.
See www.regular-expressions.info and PCRE Pattern Syntax for more info on how regexps work.
You can try
$str = "http://www.amazon.com/LEGO-Ultimate-Building-Set-Pieces/dp/B000NO9GT4/ref=sr_1_1?m=ATVPDKIKX0DER&s=toys-and-games&ie=UTF8&qid=1350518571&sr=1-1&keywords=lego" ;
list(,$desc,,$num,) = explode("/",parse_url($str,PHP_URL_PATH));
var_dump($desc,$num);
Output
string 'LEGO-Ultimate-Building-Set-Pieces' (length=33)
string 'B000NO9GT4' (length=10)
I'm new to regular expressions and am trying to find a string using preg_match, here's my code:
$artist = $row['ARTIST'];
$bool = preg_match("/$artist/", $description, $match);
My error is:
Unknown modifier 'C' in ...
If anyone could tell me what I'm doing wrong I'd appreciate it, thanks.
You have to escape possible special characters in your variable:
$bool = preg_match('/' . preg_quote($artist, '/') . '/', $description, $match);
preg_quote() in the PHP Manual:
preg_quote() takes str and puts a backslash in front of every
character that is part of the regular expression syntax. This is
useful if you have a run-time string that you need to match in some
text and the string may contain special regex characters.
Hint: try echoing your $artist variable and you should see which character is causing the problem
I've tried multiple functions to extract whatever between two strings, The delimiters might contain special characters, I guess that's why none worked for me.
My current function:
function between($str, $startTag, $endTag){
$delimiter = '#';
$regex = $delimiter . preg_quote($startTag, $delimiter)
. '(.*?)'
. preg_quote($endTag, $delimiter)
. $delimiter
. 's';
preg_match($regex, $str, $matches);
return $matches;
}
Example of string:
#{ST#RT}#
Text i want
#{END}#
#{ST#RT}#
Second text i want
#{END}#
How to improve that or suggest another solution to:
Support any kind of character or new lines
Extract multiple strings if found
Current Behavior: Only returns the first match, And also returns the match plus the surrounding tags which is unwanted
Use the m option for multi-line regular expressions (it allows the . character to match newlines):
preg_match('/foo.+bar/m', $str);
// ^--- this
Use preg_match_all() to get your multiple strings:
preg_match_all($regex, $str, $matches);
return $matches[1]; // an array of the strings
Edit:
The reason your current code returns the match plus the surrounding tags is because you're using return $matches. The $matches array has several elements in it. Index 0 is always the entire string that matched the expression. Indexes 1 and higher are your capture groups. In your expression, you had only one capture group (the "string"), so you would have wanted to only do return $matches[1] instead of return $matches.
You can use preg_match_all to extract multiple strings, besides that your code seems simple enough, normally simpler is faster.