I have a string that looks like this
../Clean_Smarty_Projekt/tpl/templates_c\.
../Clean_Smarty_Projekt/tpl/templates_c\..
I want to replace ../, \. and \.. with a regulare expression.
Before, I did this like this:
$result = str_replace(array("../","\..","\."),"",$str);
And there it (pattern) has to be in this order because changing it makes the output a little buggy. So I decided to use a regular expression.
Now I came up with this pattern
$result = preg_replace('/(\.\.\/)|(\\[\.]{1,2})/',"",$str);
What actually returns only empty strings...
Reason: (\\[\.]{1,2})
In Regex101 its all ok. (Took me a couple of minutes to realize that I don't need the /g in preg_replace)
If I use this pattern in preg_replace I have to do (\\\\[\.]{1,2}) to get it to work. But that's obviously wrong because im not searching for two slashes.
Of course I know the escaping rulse (escaping slashes).
Why doesn't this match correctly ?
I suggest you to use a different php delimiter. Within the / delimiter, you need to use three \\\ or four \\\\ backslashes to match a single backslash.
$string = '../Clean_Smarty_Projekt/tpl/templates_c\.'."\n".'../Clean_Smarty_Projekt/tpl/templates_c\..';
echo preg_replace('~\.\./|\\\.{1,2}~', '', $string)
Output:
Clean_Smarty_Projekt/tpl/templates_c
Clean_Smarty_Projekt/tpl/templates_c
I'm trying to make a replace in a string with a regex, and I really hope the community can help me.
I have this string :
031,02a,009,a,aaa,AZ,AZE,02B,975,135
And my goal is to remove the opposite of this regex
[09][0-9]{2}|[09][0-9][A-Za-z]
i.e.
a,aaa,AZ,AZE,135
(to see it in action : http://regexr.com?3795f )
My final goal is to preg_replace the first string to only get
031,02a,009,02B,975
(to see it in action : http://regexr.com?3795f )
I'm open to all solution, but I admit that I really like to make this work with a preg_replace if it's possible (It became something like a personnal challenge)
Thanks for all help !
As #Taemyr pointed out in comments, my previous solution (using a lookbehind assertion) was incorrect, as it would consume 3 characters at a time even while substrings weren't always 3 characters.
Let's use a lookahead assertion instead to get around this:
'/(^|,)(?![09][0-9]{2}|[09][0-9][A-Za-z])[^,]*/'
The above matches the beginning of the string or a comma, then checks that what follows does not match one of the two forms you've specified to keep, and given that this condition passes, matches as many non-comma characters as possible.
However, this is identical to #anubhava's solution, meaning it has the same weakness, in that it can leave a leading comma in some cases. See this Ideone demo.
ltriming the comma is the clean way to go there, but then again, if you were looking for the "clean way to go," you wouldn't be trying to use a single preg_replace to begin with, right? Your question is whether it's possible to do this without using any other PHP functions.
The anwer is yes. We can take
'/(^|,)foo/'
and distribute the alternation,
'/^foo|,foo/'
so that we can tack on the extra comma we wish to capture only in the first case, i.e.
'/^foo,|,foo/'
That's going to be one hairy expression when we substitute foo with our actual regex, isn't it. Thankfully, PHP supports recursive patterns, so that we can rewrite the above as
'/^(foo),|,(?1)/'
And there you have it. Substituting foo for what it is, we get
'/^((?![09][0-9]{2}|[09][0-9][A-Za-z])[^,]*),|,(?1)/'
which indeed works, as shown in this second Ideone demo.
Let's take some time here to simplify your expression, though. [0-9] is equivalent to \d, and you can use case-insensitive matching by adding /i, like so:
'/^((?![09]\d{2}|[09]\d[a-z])[^,]*),|,(?1)/i'
You might even compact the inner alternation:
'/^((?![09]\d(\d|[a-z]))[^,]*),|,(?1)/i'
Try it in more steps:
$newList = array();
foreach (explode(',', $list) as $element) {
if (!preg_match('/[09][0-9]{2}|[09][0-9][A-Za-z]/', $element) {
$newList[] = $element;
}
}
$list = implode(',', $newList);
You still have your regex, see! Personnal challenge completed.
Try matching what you want to keep and then joining it with commas:
preg_match_all('/[09][0-9]{2}|[09][0-9][A-Za-z]/', $input, $matches);
$result = implode(',', $matches);
The problem you'll be facing with preg_replace is the extra-commas you'll have to strip, cause you don't just want to remove aaa, you actually want to remove aaa, or ,aaa. Now what when you have things to remove both at the beginning and at the end of the string? You can't just say "I'll just strip the comma before", because that might lead to an extra comma at the beginning of the string, and vice-versa. So basically, unless you want to mess with lookaheads and/or lookbehinds, you'd better do this in two steps.
This should work for you:
$s = '031,02a,009,a,aaa,AZ,AZE,02B,975,135';
echo ltrim(preg_replace('/(^|,)(?![09][0-9]{2}|[09][0-9][A-Za-z])[^,]+/', '', $s), ',');
OUTPUT:
031,02a,009,02B,975
Try this:
preg_replace('/(^|,)[1-8a-z][^,]*/i', '', $string);
this will remove all substrings starting with the start of the string or a comma, followed by a non allowed first character, up to but excluding the following comma.
As per #GeoffreyBachelet suggestion, to remove residual commas, you should do:
trim(preg_replace('/(^|,)[1-8a-z][^,]*/i', '', $string), ',');
all,
I am using preg_match to filter some data, and it is strange that, it dose not work correctly. I am new to regex, and I used a php live regex website to check my regex, which works correctly. So I have no idea what is wrong here.
I would like to have preg_match to find something like "a\_b" in the $string:
$string="aaa\_bbb:ccc"
if(preg_match("/[a-zA-Z]\\_[a-zA-Z]/", $string)){
$snew = str_replace('\_', "_", $string);
}
But it is strange that even I have a $string like in this example above, the result of preg_match is 0. But when I change it to
preg_match("/\\_[a-zA-Z]/", $string)
It works fine and return 1. But of course that is not what I want. Any idea?
Thanks very much~
You don't really need the preg_match at all, from what I can see.
However the problem you're having with it is to do with escaping.
You have this: "/[a-zA-Z]\\_[a-zA-Z]/"
You've correctly identified that the backslash needs to be escaped, however, you've missed a subtle issue:
Regular expressions in PHP are strings. This means that you need to escape it as a string as well as a regular expression. In effect, this means that to correctly escape a backslash so it is matched as an actual backslash character in your pattern, you actually need to have four backslashes.
"/[a-zA-Z]\\\\_[a-zA-Z]/"
It's not pretty, but that's how it is.
Hope that helps.
use:
if(preg_match("/[a-zA-Z]\\\\_[a-zA-Z]/", $string))
instead
You don't need the preg_match altogether, instead just do a replace using this regex:
/([a-zA-Z])\\\\_([a-zA-Z])/
and then replace with $1_$2, like this:
$result = preg_replace("/([a-zA-Z])\\\\_([a-zA-Z])/", "$1_$2$, $string);
I need a regular expression for php that outputs everything between <!--:en--> and <!--:-->.
So for <!--:en-->STRING<!--:--> it would output just STRING.
EDIT: oh and the following <!--:--> nedds to be the first one after <!--:en--> becouse there are more in the text..
The one you want is actually not too complicated:
/<!--:en-->(.*?)<!--:-->/gi
Your matches will be in capture group 1.
Explanation:
The .*? is a lazy quantifier. Basically, it means "keep matching until you find the shortest string that will still fit this pattern." This is what will cause the matching to stop at the first instance of <!--:-->, rather than sucking up everything until the last <!--:--> in the document.
Usage is something like preg_match("/<!--:en-->(.*?)<!--:-->/gi", $input) if I recall my PHP correctly.
If you have just that input
$input = '<!--:en-->STRING<!--:-->';
You can try with
$output = strip_tags($input);
Try:
^< !--:en-- >(.*)< !--:-- >$
I don't think any of the other characters need to be escaped.
<!--:en--\b[^>]*>(.*?)<!--:-->
This will match the things between your tags. This will break if you nest your tags, but you didnt say you were doing that :)
Since I am completely useless at regex and this has been bugging me for the past half an hour, I think I'll post this up here as it's probably quite simple.
hey.exe
hey2.dll
pomp.jpg
In PHP I need to extract what's between the <a> tags example:
hey.exe
hey2.dll
pomp.jpg
Avoid using '.*' even if you make it ungreedy, until you have some more practice with RegEx. I think a good solution for you would be:
'/<a[^>]+>([^<]+)<\/a>/i'
Note the '/' delimiters - you must use the preg suite of regex functions in PHP. It would look like this:
preg_match_all($pattern, $string, $matches);
// matches get stored in '$matches' variable as an array
// matches in between the <a></a> tags will be in $matches[1]
print_r($matches);
This appears to work:
$pattern = '/<a.*?>(.*?)<\/a>/';
([^<]*)
I found this regular expression tester to be helpful.
Here is a very simple one:
<a.*>(.*)</a>
However, you should be careful if you have several matches in the same line, e.g.
hey.exehey2.dll
In this case, the correct regex would be:
<a.*?>(.*?)</a>
Note the '?' after the '*' quantifier. By default, quantifiers are greedy, which means they eat as much characters as they can (meaning they would return only "hey2.dll" in this example). By appending a quotation mark, you make them ungreedy, which should better fit your needs.