I have a text like:
This is a {demo} phrase made for {test}
I need to get
demo
test
Note: My text can have more than one block of {}, not always two. Example:
This is a {demo} phrase made for {test} written in {English}
I used this expression /{([^}]*)}/ with preg_match but it returns only the first word, not all words inside the text.
Use preg_match_all instead:
preg_match_all($pattern, $input, $matches);
It's much the same as preg_match, with the following stipulations:
Searches subject for all matches to the regular expression given in
pattern and puts them in matches in the order specified by flags.
After the first match is found, the subsequent searches are continued
on from end of the last match.
Your expression is correct, but you should be using preg_match_all() instead to retrieve all matches. Here's a working example of what that would look like:
$s = 'This is a {demo} phrase made for {test}';
if (preg_match_all('/{([^}]*)}/', $s, $matches)) {
echo join("\n", $matches[1]);
}
To also capture the positions of each match, you can pass PREG_OFFSET_CAPTURE as the fourth parameter to preg_match_all. To use that, you can use the following example:
if (preg_match_all('/{([^}]*)}/', $s, $matches, PREG_OFFSET_CAPTURE)) {
foreach ($matches[1] as $match) {
echo "{$match[0]} occurs at position {$match[1]}\n";
}
}
As the { and } are part of regex matching syntax, you need to escape these characters:
<?php
$text = <<<EOD
this {is} some text {from}
which I {may} want to {extract}
some words {between} brackets.
EOD;
preg_match_all("!\{(\w+)\}!", $text, $matches);
print_r($matches);
?>
produces
Array
(
[0] => Array
(
[0] => {is}
[1] => {from}
[2] => {may}
[3] => {extract}
[4] => {between}
)
... etc ...
)
This example may be helpful to understand the use of curly brackets in regexes:
<?php
$str = 'abc212def3456gh34ij';
preg_match_all("!\d{3,}!", $str, $matches);
print_r($matches);
?>
which returns:
Array
(
[0] => Array
(
[0] => 212
[1] => 3456
)
)
Note that '34' is excluded from the results because the \d{3,} requires a match of at least 3 consecutive digits.
Matching portions between pair of braces using RegEx, is less better than using Stack for this purpose. Using RegEx would be something like «quick and dirty patch», but for parsing and processing input string you have to use a stack. Visit here for the concept and here for applying the same.
Related
I have tried the non capturing group option ?:
Here is my data:
hello:"abcdefg"},"other stuff
Here is my regex:
/hello:"(.*?)"}/
Here is what it returns:
Array
(
[0] => Array
(
[0] => hello:"abcdefg"}
)
[1] => Array
(
[0] => abcdefg
)
)
I wonder, how can I make it so that [0] => abdefg and that [1] => doesnt exist?
Is there any way to do this? I feel like it would be much cleaner and improve my performance. I understand that regex is simply doing what I told it to do, that is showing me the whole string that it found, and the group inside the string. But how can I make it only return abcdefg, and nothing more? Is this possible to do?
Thanks.
EDIT: I am using the regex on a website that says it uses perl regex. I am not actually using the perl interpreter
EDIT Again: apparently I misread the website. It is indeed using PHP, and it is calling it with this function: preg_match_all('/hello:"(.*?)"}/', 'hello:"abcdefg"},"other stuff', $arr, PREG_PATTERN_ORDER);
I apologize for this error, I fixed the tags.
EDIT Again 2: This is the website http://www.solmetra.com/scripts/regex/index.php
preg_match_all
If you want a different captured string, you need to change your regex. Here I'm looking for anything not a double quote " between two quote " characters behind a : colon character.
<?php
$string = 'hello:"abcdefg"},"other stuff';
$pattern = '!(?<=:")[^"]+(?=")!';
preg_match_all($pattern,$string,$matches);
echo $matches[0][0];
?>
Output
abcdefg
If you were to print_r($matches) you would see that you have the default array and the matches in their own additional arrays. So to access the string you would need to use $matches[0][0] which provides the two keys to access the data. But you're always going to have to deal with arrays when you're using preg_match_all.
Array
(
[0] => Array
(
[0] => abcdefg
)
)
preg_replace
Alternatively, if you were to use preg_replace instead, you could replace all of the contents of the string except for your capture group, and then you wouldn't need to deal with arrays (but you need to know a little more about regex).
<?php
$string = 'hello:"abcdefg"},"other stuff';
$pattern = '!^[^:]+:"([^"]+)".+$!s';
$new_string = preg_replace($pattern,"$1",$string);
echo $new_string;
?>
Output
abcdefg
preg_match_all is returning exactly what is supposed to.
The first element is the entire string that matched the regex. Every other element are the capture groups.
If you just want the the capture group, then just ignore the 1st element.
preg_match_all('/hello:"(.*?)"}/', 'hello:"abcdefg"},"other stuff', $arr, PREG_PATTERN_ORDER);
$firstMatch = $arr[1];
I have a string like this:
page-9000,page-template,page-type,page-category-128,image-195,listing-latest,rss-latest,even-more-info,even-more-tags
I made this regex that I expect to get the whole tags with:
(?<=\,)(rss-latest|listing-latest-no-category|category-128|page-9000)(?=\,)
I want it to match all the ocurrences.
In this case:
page-9000 and rss-latest.
This regex checks whole words between commas just fine but it ignores the first and the last because it's not between commas (obviously).
I've also tried that it checks if it's between commas OR one comma at the beginning OR one comma to the end, however it would give me false positives, as it would match:
category-128
while the string contains:
page-category-128
Any help?
Try using the following pattern:
(?<=,|^)(rss-latest|listing-latest-no-category|category-128|page-9000)(?=,|$)
The only change I have made is to add boundary markers ^ and $ to the lookarounds to also match on the start and end of the input.
Script:
$input = "page-9000,page-template,page-type,page-category-128,image-195,listing-latest,rss-latest,even-more-info,even-more-tags";
preg_match_all("/(?<=,|^)(rss-latest|listing-latest-no-category|category-128|page-9000)(?=,|$)/", $input, $matches);
print_r($matches[1]);
This prints:
Array
(
[0] => page-9000
[1] => rss-latest
)
Here is a non-regex way using explode and array_intersect:
$arr1 = explode(',', 'page-9000,page-template,page-type,page-category-128,image-195,listing-latest,rss-latest,even-more-info,even-more-tags');
$arr2 = explode('|', 'rss-latest|listing-latest-no-category|category-128|page-9000');
print_r(array_intersect($arr1, $arr2));
Output:
Array
(
[0] => page-9000
[6] => rss-latest
)
The (?<=\,) and (?=,) require the presence of , on both sides of the matching pattern. You want to match also at the start/end of string, and this is where you need to either explicitly tell to match either , or start/end of string or use double-negating logic with negated character classes inside negative lookarounds.
You may use
(?<![^,])(?:rss-latest|listing-latest-no-category|category-128|page-9000)(?![^,])
See the regex demo
Here, (?<![^,]) matches the start of string position or a , and (?![^,]) matches the end of string position or ,.
Now, you do not even need a capturing group, you may get rid of its overhead using a non-capturing group, (?:...). preg_match_all won't have to allocate memory for the submatches and the resulting array will be much cleaner.
PHP demo:
$re = '/(?<![^,])(?:rss-latest|listing-latest-no-category|category-128|page-9000)(?![^,])/m';
$str = 'page-9000,page-template,page-type,page-category-128,image-195,listing-latest,rss-latest,even-more-info,even-more-tags';
if (preg_match_all($re, $str, $matches)) {
print_r($matches[0]);
}
// => Array ( [0] => page-9000 [1] => rss-latest )
In PHP, I have strings like so:
$string = "This is a 123 test (your) string (for example 1234) to test.";
From that string, I'd like to get the words inside the () with the numbers. I've tried using explode but since I have 2 word/group of strings enclosed in the parentheses, I end up getting (your) instead of (for example 1234). I've also used substr like so:
substr($string, -20)
This works most of the time but the problem with this is, there are instances that the string is shorter so it ends up getting even the unwanted string. I've also tried using regular expression in which I set something like so:
/[^for]/
but that did not work either. The string I want to get always starts with "for" but the length varies. How do I manipulate php so that I can get only the string enclosed inside the parentheses that starts with the word for?
I might use preg_match() in this case.
preg_match("#\((for.*?)\)#",$string,$matches);
Any matches found would be stored in $matches.
Use the following regular expression:
(\(for.*?\))
It will capture patterns like:
(for)
(foremost)
(for example)
(for 1)
(for: 1000)
A sample PHP code:
$pattern = '/(\(for.*?\))/';
$result = preg_match_all(
$pattern,
" text (for example 1000) words (for: 20) other words",
$matches
);
if ( $result > 0 ) {
print_r( $matches );
}
Above print_r( $matches ) result:
Array
(
[0] => Array
(
[0] => (for example 1000)
[1] => (for: 20)
)
[1] => Array
(
[0] => (for example 1000)
[1] => (for: 20)
)
)
Use preg_match for regular expression
$matches = array();
$pattern = '/^for/i';
preg_match($pattern,$string,$matches);
pirnt_r($matches);
If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.
$matches = array();
preg_match("/(\(for[\w\d\s]+\))/i",$string,$matches);
var_dump($matches);
I have tried the non capturing group option ?:
Here is my data:
hello:"abcdefg"},"other stuff
Here is my regex:
/hello:"(.*?)"}/
Here is what it returns:
Array
(
[0] => Array
(
[0] => hello:"abcdefg"}
)
[1] => Array
(
[0] => abcdefg
)
)
I wonder, how can I make it so that [0] => abdefg and that [1] => doesnt exist?
Is there any way to do this? I feel like it would be much cleaner and improve my performance. I understand that regex is simply doing what I told it to do, that is showing me the whole string that it found, and the group inside the string. But how can I make it only return abcdefg, and nothing more? Is this possible to do?
Thanks.
EDIT: I am using the regex on a website that says it uses perl regex. I am not actually using the perl interpreter
EDIT Again: apparently I misread the website. It is indeed using PHP, and it is calling it with this function: preg_match_all('/hello:"(.*?)"}/', 'hello:"abcdefg"},"other stuff', $arr, PREG_PATTERN_ORDER);
I apologize for this error, I fixed the tags.
EDIT Again 2: This is the website http://www.solmetra.com/scripts/regex/index.php
preg_match_all
If you want a different captured string, you need to change your regex. Here I'm looking for anything not a double quote " between two quote " characters behind a : colon character.
<?php
$string = 'hello:"abcdefg"},"other stuff';
$pattern = '!(?<=:")[^"]+(?=")!';
preg_match_all($pattern,$string,$matches);
echo $matches[0][0];
?>
Output
abcdefg
If you were to print_r($matches) you would see that you have the default array and the matches in their own additional arrays. So to access the string you would need to use $matches[0][0] which provides the two keys to access the data. But you're always going to have to deal with arrays when you're using preg_match_all.
Array
(
[0] => Array
(
[0] => abcdefg
)
)
preg_replace
Alternatively, if you were to use preg_replace instead, you could replace all of the contents of the string except for your capture group, and then you wouldn't need to deal with arrays (but you need to know a little more about regex).
<?php
$string = 'hello:"abcdefg"},"other stuff';
$pattern = '!^[^:]+:"([^"]+)".+$!s';
$new_string = preg_replace($pattern,"$1",$string);
echo $new_string;
?>
Output
abcdefg
preg_match_all is returning exactly what is supposed to.
The first element is the entire string that matched the regex. Every other element are the capture groups.
If you just want the the capture group, then just ignore the 1st element.
preg_match_all('/hello:"(.*?)"}/', 'hello:"abcdefg"},"other stuff', $arr, PREG_PATTERN_ORDER);
$firstMatch = $arr[1];
In PHP, I need to split a string by ":" characters without a leading "*".
This is what using explode() does:
$string = "1*:2:3*:4";
explode(":", $string);
output: array("1*", "2", "3*", "4")
However the output I need is:
output: array("1*:2", "3*:4")
How would I achieve the desired output?
You're probably looking for preg_match_all() rather than explode(), as you are attempting a more complex split than explode() itself can handle. preg_match_all() will allow you to gather all of the parts of a string that match a specific pattern, expressed using a regular expression. The pattern you are looking for is something along the lines of:
anything except : followed by *: followed by anything but :
So, try this instead:
preg_match_all('/[^:]+\*:[^:]+/', $string, $matches);
print_r($matches);
Which will output something like:
Array
(
[0] => Array
(
[0] => 1*:2
[1] => 3*:4
)
)
Which you should be able to use in much the same way that you would use the results of explode() even if there is the added dimension in the array (it divides the matches into 'groups', and all your results match against the whole expression or the first (0th) group).
$str = '1*:2:3*:4';
$res = preg_split('~(?<!\*):~',$str);
print_r($res);
will output
Array
(
[0] => 1*:2
[1] => 3*:4
)
The pattern basically says:
split by [a colon that is not lead by an asterisk]