I'm trying to match the following array-like pattern with regex:
foo[bar][baz][bim]
I almost have it with the following regex:
~([^[]+)(?:\[(.+?)\])*~gm
However, the capturing groups only include:
Full match: foo[bar][baz][bim]
Group 1: foo
Group 2: bim
I can't figure out why it's only capturing the last occurrence of the [] structure. I'd like it capture foo, bar, baz, and bim in this case.
Any ideas on what I'm missing?
Repeated capturing groups in PCRE don't remember the values of each previous pattern. For this you need to invoke \G token:
(?|(\w+)|\G(?!\A)\[([^][]*)\])
See live demo here
Regex breakdown:
(?| Start of a branch reset group
(\w+) Capture word characters
| Or
\G(?!\A) Conitnue from where previous match ends
\[ Match an opening bracket
([^][]*) Capture any thing except [ and ]
\] Match a closing bracket
) End of cluster
PHP code:
preg_match_all('~(?|(\w+)|\G(?!\A)\[([^][]*)\])~', 'foo[bar][baz][bim]', $matches);
print_r($matches[1]);
This can also be parsed without regex.
Remove the closing ] and then explode on the opening [.
$str = "foo[bar][baz][bim]";
$str = str_replace("]","",$str);
$arr = explode("[", $str);
var_dump($arr);
Returns:
array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(3) "bim"
}
Where the first item is the "array" name and the following is the children/path.
Related
I have this string: ATL.556808.UMO20.02 and I want to get only UMO20.02.
Here is my preg_match:
$e = preg_match('"\.[^\.]+\.(.*?)$"si', $t, $m);
But this code return two matches instead of one. I got:
array(2) {
[0]=> string(16) ".556808.UMO20.02"
[1]=> string(8) "UMO20.02"
}
But I want to get one match:
array(1) {
[0]=> string(8) "UMO20.02"
}
Where is the problem?
You don't have to use the s and i flags as there are no specific cases for upper or lowercase chars, and the dot does not have to match a newline in the example data.
You can use
\.[^.]+\.\K.+$
\. Match .
[^.]+\. Match 1+ times any char except a .
\K Forget what is matched
.+ Match any char 1+ times
$ End of string
Regex demo
Example code
$re = '/\.[^.]+\.\K.+$/';
$str = 'ATL.556808.UMO20.02';
preg_match($re, $str, $matches);
print_r($matches);
Output
Array
(
[0] => UMO20.02
)
Your \.[^\.]+\.(.*?)$ regex matches a ., then any one or more chars other than a dot, then a dot, and then any zero or more chars as few as possible (but as many as necessary to complete a match) up to the end of string. The .*? must be tempered to match any chars but dots.
To remove all up to and including the second dot, you can use
$t = 'ATL.556808.UMO20.02';
echo preg_replace('~^(?:[^.]+\.){2}~', '', $t);
// => UMO20.02
See the PHP demo. See the regex demo. Details:
^ - start of string
(?:[^.]+\.){2} - two occurrences of any one or more chars other than a . and then a . char
I have an input that goes like this
[d/D/d1/d2/d3/d4/d5/d6/d7/D1/D2/D3/D4/D5/D6/D7]+[\.]+[r1/r2/r3/r4/r5/r6/R1/R2/R3/R4/R5/R6]+[\.]+[number 1 to 37]+[#]+[number 0 - 9 ]
An example would be "d2.r1.4#100.37#1.9#2.3#1(can have as many 1-37 # 0-9 as needed)"
How do I write a regex match that can allow the last part of the string to be dynamic (matches as many groups as needed as inputted)
I've tried this expression:
[dD1-7]+\.[rR1-5]+\.
and I'm not sure how to match the dynamic group that comes after the "d2.r1." part.
Assuming you merely need to validate the string (and not capture/extract specific substrings), the following pattern provides the same result as Emma's answer but with a tighter syntax.
The i pattern modifier means you only have to write the two letters in lowercase. I don't use any excess non-capturing groups. Two-character character classes don't need a hyphen. \d is the shorter way of expressing [0-9].
Wrapping the final/repeating characters in parentheses then writing * means the sequence in the parentheses may repeat zero or more times.
Code: (Demo)
$inputs = [
'd2.r1.4#100.37#1.9#2.3#1',
'd2.r1.4#100.37#1.9#2.38#1.8#22',
'd2.r1.4#100.37#1.9#2.3#1.12#2.30#2',
];
$pattern = '/^d[1-7]\.r[1-6](?:\.(?:3[0-7]|[12]\d|[1-9])#\d+)*$/i';
foreach ($inputs as $input) {
echo "\n{$input}: ";
var_export((bool)preg_match($pattern, $input));
}
Output:
d2.r1.4#100.37#1.9#2.3#1: true
d2.r1.4#100.37#1.9#2.38#1.8#22: false
d2.r1.4#100.37#1.9#2.3#1.12#2.30#2: true
I'm guessing that maybe some expression similar to,
^[dD][1-7]\.[rR][1-6](?:(?:\.(?:3[0-7]|[1-2]\d|[1-9]))#[0-9]+)*$
or with some slight changes, would likely work here.
Test
$re = '/^[dD][1-7]\.[rR][1-6](?:(?:\.(?:3[0-7]|[1-2]\d|[1-9]))#[0-9]+)*$/m';
$str = 'd2.r1.4#100.37#1.9#2.3#1
d2.r1.4#100.37#1.9#2.3#1.37#1.9#2.3#1.37#1.9#2.3#1.37#1.9#2.3#1
d2.r1.4#100.38#1.9#2.3#1
d2.r1.4#100.0#1.9#2.3#1
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
var_dump($matches);
Output
array(2) {
[0]=>
array(1) {
[0]=>
string(24) "d2.r1.4#100.37#1.9#2.3#1"
}
[1]=>
array(1) {
[0]=>
string(63) "d2.r1.4#100.37#1.9#2.3#1.37#1.9#2.3#1.37#1.9#2.3#1.37#1.9#2.3#1"
}
}
If you wish to simplify/modify/explore the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.
RegEx Circuit
jex.im visualizes regular expressions:
I have one of the four patter:
"Test"
'Test'
`Test`
(Test)
Is it possible to get "Test" with a single preg_match call?
I tried the following:
if ( preg_match( '/^(?:"(.*)"|\'(.*)\'|`(.*)`|\((.*)\')$/iu', $pattern, $matches ) )
... but this gives me five elements of $matches back. But I would like to have two only (One for the whole match and one for the found match with "Test" in it.)
To make sure that the single quote, back tick and double quote and have the same closing char you might use a capturing group with a backreference to that group.
To get the same group in the alternation to also match ( with the closing ) you might use a branch reset group.
The match for Test is in group 2
(?|(["'`])(Test)\1|\(((Test)\)))
Explanation
(?| Branch reset group
(["'`]) Capture in group 1 any of the listed
(Test)\1 Capture in group 2 matching Test followed by a backreference \1 to group 1
| Or
\(((Test)\)) Match (, capture in group 2 matching Test followed by )
) Close branch reset group
Regex demo | Php demo
For example:
$strings = [
"\"Test\"",
"'Test'",
"`Test`",
"(Test)",
"Test\"",
"'Test",
"Test`",
"(Test",
"\"Test'",
"'Test\"",
"`Test",
"Test)",
];
$pattern = '/(?|(["\'`])(Test)\1|\(((Test)\)))/';
foreach ($strings as $string){
$isMatch = preg_match($pattern, $string, $matches);
if ($isMatch) {
echo "Match $string ==> " . $matches[2] . PHP_EOL;
}
}
Result
Match "Test" ==> Test
Match 'Test' ==> Test
Match `Test` ==> Test
Match (Test) ==> Test
You can use dot to match the characters aroun d the word and use array_unique to remove duplicates.
preg_match_all("/.(\w+)./", $str,$match);
foreach($match as &$m) $m = array_unique($m);
var_dump($match);
https://3v4l.org/T2hnh
array(2) {
[0]=>
array(4) {
[0]=>
string(6) ""Test""
[1]=>
string(6) "'Test'"
[2]=>
string(6) "`Test`"
[3]=>
string(6) "(Test)"
}
[1]=>
&array(1) {
[0]=>
string(4) "Test"
}
}
You can use non-capturing groups :
'/^(?:"|\'|`|\()(.*)(?:"|\'|`|\))$/iu'
So just the (.*) group will capture data.
Your regex could be:
^['"`(](.+)['"`)]$
Which would give off the following code in PHP:
if(preg_match('^[\'"`(](.+)[\'"`)]$', $pattern, $matches))
Explanation
In Regex, character groups—marked with enclosing square brackets []— matches one of the characters inside of it.
I want to replace some template tags:
$tags = '{name} text {first}';
preg_match_all('~\{(\w+)\}~', $tags, $matches);
var_dump($matches);
output is:
array(2) {
[0]=> array(2) {
[0]=> string(6) "{name}"
[1]=> string(7) "{first}"
}
[1]=> array(2) {
[0]=> string(4) "name"
[1]=> string(5) "first"
}
}
why are there inside 2 arrays? How to achieve only second one?
The sort answer:
Is there an alternative? Of course there is: lookaround assertions allow you to use zero-width (non-captured) single char matches easily:
preg_match_all('/(?<=\{)\w+(?=})/', $tags, $matches);
var_dump($matches);
Will dump this:
array(1) {
[0]=>
array(2) {
[0]=>
string(4) "name"
[1]=>
string(5) "first"
}
}
The pattern:
(?<=\{): positive lookbehind - only match the rest of the pattern if there's a { character in front of it (but don't capture it)
\w+: word characters are matches
(?=}): only match preceding pattern if it is followed by a } character (but don't capture the } char)
It's that simple: the pattern uses the {} delimiter chars as conditions for the matches, but doesn't capture them
Explaining this $matches array structure a bit:
The reason why $matches looks the way it does is quite simple: when using preg_match(_all), the first entry in the match array will always be the entire string matched by the given regex. That's why I used zero-width lookaround assertions, instead of groups. Your expression matches "{name}" in its entirety, and extracts "name" through grouping.
The matches array will hold the full match on index 0, and add groups at every subsequent index, in your case that means that:
$matches[0] will contain all substrings matching /\{\w+\}/ as a pattern.
$matches[1] will contain all substrings that were captured (/\{(\w+)\}/ captures (\w+)).
If you were to have a regex like this: /\{((\w)([^}]+))}/ the matches array will look something like this:
[
0 => [
'{name}',//as if you'd written /\{\w[^}]+}/
],
1 => [
'name',//matches group (\w)([^}]+), as if you wrote (\w[^}]+)
],
2 => [
'n',//matches (\w) group
],
3 => [
'ame',//and this is the ([^}]+) group obviously
]
]
Why? simple because the pattern contains 3 matching groups. Like I said: the first index in the matches array will always be the full match, regardless of capture groups. The groups are then appended to the array in the order the appear in in the expression. So if we analyze the expression:
\{: not matches, but part of the pattern, will only be in the $matches[0] values
((\w)([^}]+)): Start of first matching group, \w[^}]+ match is grouped here, $matches[1] will contain these values
(\w): Second group, a single \w char (ie first character after {. $matches[2] will therefore contain all first characters after a {
([^}]+): Third group, matches rest of string after {\w until a } is encountered, this will make out the $matches[3] values
To better understand, and be able to predict the way $matches will get populated, I'd strongly recommend you use this site: regex101. Write your expression there, and it'll break it all down for you on the right hand side, listing the groups. For example:
/\{((\w)([^}]+))}/
Is broken down like this:
/\{((\w)([^}]+))}/
\{ matches the character { literally
1st Capturing group ((\w)([^}]+))
2nd Capturing group (\w)
\w match any word character [a-zA-Z0-9_]
3rd Capturing group ([^}]+)
[^}]+ match a single character not present in the list below
Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy]
} the literal character }
} matches the character } literally
Looking at the capturing groups, you can now confidently say what $matches will look like, and you can safely say that $matches[2] will be an array of single characters.
Of course, this may leave you wondering why $matches is a 2D array. Well, that again is really quite easy: What you can predict is how many match indexes a $matches array will contain: 1 for the full pattern, then +1 for each capture group. What you Can't predict, though, is how many matches you'll find.
So what preg_match_all does is really quite simple: fill $matches[0] with all substrings that match the entire pattern, then extract each group substring from these matches and append that value onto the respective $matches arrays. In other words, the number of arrays that you can find in $matches is a given: it depends on the pattern. The number of keys you can find in the sub-arrays of $matches is an unknown, it depends on the string you're processing. If preg_match_all were to return a 1D array, it would be a lot harder to process the matches, now you can simply write this:
$total = count($matches);
foreach ($matches[0] as $k => $full) {
echo $full . ' contains: ' . PHP_EOL;
for ($i=1;$i<$total;++$i) {
printf(
'Group %d: %s' . PHP_EOL,
$i, $matches[$i][$k]
);
}
}
If preg_match_all created a flat array, you'd have to keep track of the amount of groups in your pattern. Whenever the pattern changes, you'd also have make sure to update the rest of the code to reflect the changes made to the pattern, making your code harder to maintain, whilst making it more error-prone, too
Thats because your regex could have multiple match groups - if you have more (..) you would have more entries in your array. The first one[0] ist always the whole match.
If you want an other order of the array, you could use PREG_SET_ORDER as the 4. argument for preg_match_all. Doing this would result in the following
array(2) {
[0]=> array(2) {
[0]=> string(6) "{name}"
[1]=> string(7) "name"
}
[1]=> array(2) {
[0]=> string(4) "{first}"
[1]=> string(5) "first"
}
}
this could be easier if you loop over your result in a foreach loop.
If you only interessted in the first match - you should stay with the default PREG_PATTERN_ORDER and just use $matches[1]
I have the string: This is a [[bla]] and i want a [[burp]] and i need to put in an array the 2 string [[bla]] and [[burp]].
The regexp i am trying to use is:
$pattern = "/\[\[.+\]\]/"
The problem is that the output is: [[bla]] and [[burp]] ,because i suppose it take the first [[ with the last ]]
How can i fix the pattern?
Make it ungreedy, see it on Regexr
/\[\[.+?\]\]/
or use a negated character class, see it on Regexr
/\[\[[^\]]+\]\]/
You need ungreedy repitition (lazy) matching here -> *? to get only the text between [[ ]] and not between [[ ]] [[ ]]:
$pattern = "/\[\[(.*?)\]\]/"
Also you need a matching group to get only the text between the square brackets and not the brackets itself -> (.*?)
Example:
$string = "This is a [[bla]] and i want a [[burp]]";
$pattern = "/\[\[(.*?)\]\]/";
preg_match_all($pattern , $string, $matches);
var_dump($matches[1]);
Output:
array(2) {
[0]=>
string(3) "bla"
[1]=>
string(4) "burp"
}