I'm a beginner in regular expression so it didn't take long for me to get totally lost :]
What I need to do:
I've got a string of values 'a:b,a2:b2,a3:b3,a4:b4' where I need to search for a specific pair of values (ie: a2:b2) by the second value of the pair given (b2) and get the first value of the pair as an output (a2).
All characters are allowed (except ',' which seperates each pair of values) and any of the second values (b,b2,b3,b4) is unique (cant be present more than once in the string)
Let me show a better example as the previous may not be clear:
This is a string: 2 minutes:2,5 minutes:5,10 minutes:10,15 minutes:15,never:0
Searched pattern is: 5
I thought, the best way was to use function called preg_match with subpattern feature.
So I tried the following:
$str = '2 minutes:2,5 minutes:5,10 minutes:10,15 minutes:15,20 minutes:20,30 minutes:30, never:0';
$re = '/(?P<name>\w+):5$/';
preg_match($re, $str, $matches);
echo $matches['name'];
Wanted output was '5 minutes' but it didn't work.
I would also like to stick with Perl-Compatible reg. expressions as the code above is included in a PHP script.
Can anyone help me out? I'm getting a little bit desperate now, as Ive spent on this most of the day by now ...
Thanks to all of you guys.
$str = '2 minutes:2,51 seconds:51,5 minutes:5,10 minutes:10,15 minutes:51,never:0';
$search = 5;
preg_match("~([^,\:]+?)\:".preg_quote($search)."(?:,|$)~", $str, $m);
echo '<pre>'; print_r($m); echo '</pre>';
Output:
Array
(
[0] => 5 minutes:5
[1] => 5 minutes
)
$re = '/(?:^|,)(?P<name>[^:]*):5(?:,|$)/';
Besides the problem of your expression having to match $ after 5, which would only work if 5 were the last element, you also want to make sure that after 5 either nothing comes or another pair comes; that before the first element of the pair comes either another element or the beginning of the string, and you want to match more than \w in the first element of the pair.
A preg_match call will be shorter for certain, but I think I wouldn't bother with regular expressions, and instead just use string and array manipulations.
$pairstring = '2 minutes:2,5 minutes:5,10 minutes:10,15 minutes:15,20 minutes:20,30 minutes:30, never:0';
function match_pair($searchval, $pairstring) {
$pairs = explode(",", $str);
foreach ($pairs as $pair) {
$each = explode(":", $pair);
if ($each[1] == $searchval) {
echo $each[0];
}
}
}
// Call as:
match_pair(5, $pairstring);
Almost the same as #Michael's. It doesn't search for an element but constructs an array of the string. You say that values are unique so they are used as keys in my array:
$str = '2 minutes:2,5 minutes:5,10 minutes:10,15 minutes:15,20 minutes:20,30 minutes:30, never:0';
$a = array();
foreach(explode(',', $str) as $elem){
list($key, $val) = explode(':', $elem);
$a[$val] = $key;
}
Then accessing an element is very simple:
echo $a[5];
Related
I have a string which contains certain number of #{number} structures. For example:
#328_#918_#1358
SKU:#666:#456
TEST--#888/#982
For each #{number} structure, I have to replace it with a known string.
For the first example:
#328_#918_#1358
I have the following strings:
328="foo"
918="bar"
1358"arg"
And the result should be:
foo_bar_arg
How do I achieve such effect? My current code looks like that:
$matches = array();
$replacements = array();
// starting string
$string = "#328_#918:#1358";
// getting all the numbers from the string
preg_match_all("/\#[0-9]+/", $string, $matches);
// getting rid of #
foreach ($matches[0] as $key => &$feature) {
$feature = preg_replace("/#/", "", $feature);
} // end foreach
// obtaining the replacement values
foreach ($matches[0] as $key => $value) {
$replacement[$value] = "fizz"; // here the value required for replacement is obtained
} // end foreach
But I have no idea how to actually perform a replacement in $string variable using values from $replacement table. Any help is much appreciated!
You can use a preg_replace_callback solution:
$string = '#328_#918:#1358
SKU:#666:#456
TEST--#888/#982';
$replacements = [328=>"foo", 918=>"bar", 1358=>"arg"];
echo preg_replace_callback("/#([0-9]+)/", function ($m) use ($replacements) {
return isset($replacements[$m[1]]) ? $replacements[$m[1]] : $m[0];
}
,$string);
See the PHP demo.
The #([0-9]+) regex will match all non-overlapping occurrences of # and one or more digits right after capturing them into Group 1. If there is an item in the replacements associative array with the numeric key, the whole match is replaced with the corresponding value. Else, the match is returned so that no replacement could occur and the match does not get removed.
I am trying to get the integer on the left and right for an input from the $str variable using REGEX. But I keep getting the commas back along with the integer. I only want integers not the commas. I have also tried replacing the wildcard . with \d but still no resolution.
$str = "1,2,3,4,5,6";
function pagination()
{
global $str;
// Using number 4 as an input from the string
preg_match('/(.{2})(4)(.{2})/', $str, $matches);
echo $matches[0]."\n".$matches[1]."\n".$matches[1]."\n".$matches[1]."\n";
}
pagination();
How about using a CSV parser?
$str = "1,2,3,4,5,6";
$line = str_getcsv($str);
$target = 4;
foreach($line as $key => $value) {
if($value == $target) {
echo $line[($key-1)] . '<--low high-->' . $line[($key+1)];
}
}
Output:
3<--low high-->5
or a regex could be
$str = "1,2,3,4,5,6";
preg_match('/(\d+),4,(\d+)/', $str, $matches);
echo $matches[1]."<--low high->".$matches[2];
Output:
3<--low high->5
The only flaw with these approaches is if the number is the start or end of range. Would that ever be the case?
I believe you're looking for Regex Non Capture Group
Here's what I did:
$regStr = "1,2,3,4,5,6";
$regex = "/(\d)(?:,)(4)(?:,)(\d)/";
preg_match($regex, $regStr, $results);
print_r($results);
Gives me the results:
Array ( [0] => 3,4,5 [1] => 3 [2] => 4 [3] => 5 )
Hope this helps!
Given your function name I am going to assume you need this for pagination.
The following solution might be easier:
$str = "1,2,3,4,5,6,7,8,9,10";
$str_parts = explode(',', $str);
// reset and end return the first and last element of an array respectively
$start = reset($str_parts);
$end = end($str_parts);
This prevents your regex from having to deal with your numbers getting into the double digits.
I want to split a string such as the following (by a divider like '~##' (and only that)):
to=enquiry#test.com~##subject=test~##text=this is body/text~##date=date
into an array containing e.g.:
to => enquiry#test.com
subject => test
text => this is body/text
date => date
I'm using php5 and I've got the following regex, which almost works, but there are a couple of errors and there must be a way to do it in one go:
//Split the string in the url of $text at every ~##
$regexp = "/(?:|(?<=~##))(.*?=.*?)(?:~##|$|\/(?!.*~##))/";
preg_match_all($regexp, $text, $a);
//$a[1] is an array containing var1=content1 var2=content2 etc;
//Now create an array in the form [var1] = content, [var2] = content2
foreach($a[1] as $key => $value) {
//Get the two groups either side of the equals sign
$regexp = "/([^\/~##,= ]+)=([^~##,= ]+)/";
preg_match_all($regexp, $value, $r);
//Assign to array key = value
$val[$r[1][0]] = $r[2][0]; //e.g. $val['subject'] = 'hi'
}
print_r($val);
My queries are that:
It doesn't seem to capture more than 3 different sets of parameters
It is breaking on the # symbol and so not capturing email addresses e.g. returning:
to => enquiry
subject => test
text => this is body/text
I am doing multiple different regex searches where I suspect I would be able to do one.
Any help would be really appreciated.
Thanks
Why are you using regex when there is much simple method to do this by explode like this
$str = 'to=enquiry#test.com~##subject=test~##text=this is body/text~##date=date';
$array = explode('~##',$str);
$finalArr = array();
foreach($array as $val)
{
$tmp = explode('=',$val);
$finalArr[$tmp['0']] = $tmp['1'];
}
echo '<pre>';
print_r($finalArr);
I want to get the words in a string where a specific character stands before, in this case, its the : character.
textexjkladjladf :theword texttextext :otherword :anotherword
From this snippet the expected output will be:
theword
otherword
anotherword
How do i do this with PHP?
You can use regular expression:
$string = "textexjkladjladf :theword texttextext :otherword :anotherword";
$matches = array();
preg_match_all('/(?<=:)\w+/', $string, $matches);
foreach ($matches[0] as $item) {
echo $item."<br />";
}
Output is:
theword
otherword
anotherword
The array what you want is the $matches[0]
Another way of getting those words without Regular Expression can be:
Use explode(' ',$str) to get all the words.
Then loop the words and check which one starts with ':'.
try
$str = 'textexjkladjladf :theword texttextext :otherword :anotherword';
$tab = exlode(':',$str);
print_r($tab);
//if echo entry 0 =>
echo $tab[0]; // => textexjkladjladf
I want to grab a specific string only if a certain word is followed by a = sign.
Also, I want to get all the info after that = sign until a / is reached or the string ends.
Let's take into example:
somestring.bla/test=123/ohboy/item/item=capture
I want to get item=capture but not item alone.
I was thinking about using lookaheads but I'm not sure it this is the way to go. I appreciate any help as I'm trying to grasp more and more about regular expressions.
[^/=]*=[^/]*
will give you all the pairs that match your requirements.
So from your example it should return:
test=123
item=capture
Refiddle Demo
If you want to capture item=capture, it is straightforward:
/item=[^\/]*/
If you want to also extract the value,
/item=([^\/]*)/
If you only want to match the value, then you need to use a look-behind.
/(?<=item=)[^\/]*/
EDIT: too many errors due to insomnia. Also, screw PHP and its failure to disregard separators in a character group as separators.
Here is a function I wrote some time ago. I modified it a little, and added the $keys argument so that you can specify valid keys:
function getKeyValue($string, Array $keys = null) {
$keys = (empty($keys) ? '[\w\d]+' : implode('|', $keys));
$pattern = "/(?<=\/|$)(?P<key>{$keys})\s*=\s*(?P<value>.+?)(?=\/|$)/";
preg_match_all($pattern, $string, $matches, PREG_SET_ORDER);
foreach ($matches as & $match) {
foreach ($match as $key => $value) {
if (is_int($key)) {
unset($match[$key]);
}
}
}
return $matches ?: FALSE;
}
Just trow in the string and valid keys:
$string = 'somestring.bla/test=123/ohboy/item/item=capture';
$keys = array('test', 'item');
$keyValuePairs = getKeyValue($string, $keys);
var_dump($keyValuePairs);