replace only part of string witg preg_replace - php

I have little problem with a replacement of a little part in an url.
I have an url with some queries that I build with http_build_query().
In that url i have a query like angle_30. What I want is to remove the _30 so the query becomes angle.
How can I do that with preg_replace?
I have created a search and replacement array
$search_pattern = array();
$search_pattern[0] = "/([?&]newpage)=[^&]*/";
$search_pattern[1] = "/([?&]next)=[^&]*/";
$search_replacements = array();
$search_replacements[0] = '';
$search_replacements[1] = '';
which works fine. I just want to extend it with the angle replacement.

Here is a search and replacement pattern that replaces "angle_", followed by an arbitrary number of digits with "angle".
$search_pattern[2] = "/angle_\d+/";
$search_replacements[2] = "angle";

Related

How to change integer value in preg_match PHP?

sorry if my question was stupid, please someone help me to fix this issue.
i have string like
$str_value = "http://99.99.99.99/var/test/src/158-of-box.html/9/";
this $str_value is dynamic , it will change each page. now i need to replace 9 in this string as 10. add integer 1 and replace
for example if the $str_value = "http://99.99.99.99/var/test/src/158-of-box.html/251/"
then output should be
http://99.99.99.99/var/test/src/158-of-box.html/252/
i tried to replace using preg_match but i m getting wrong please somesone help me
$str = preg_replace('/[\/\d+\/]/', '10',$str_value );
$str = preg_replace('/[\/\d+\/]/', '[\/\d+\/]+1',$str_value );
Thank's for the answer, #Calimero! You've been faster than me, but I would like to post my answer, too ;-)
Another possibilty is to fetch the integer by using a group. So you don't need to trim $matches[0] to remove the slashes.
$str_value = "http://99.99.99.99/var/test/src/158-of-box.html/9/";
$str = preg_replace_callback('/\/([\d+])\//', function($matches) {
return '/'.($matches[1]+1).'/';
}, $str_value);
echo $str;
You need to use a callback to increment the value, it cannot be done directly in the regular expression itself, like so :
$lnk= "http://99.99.99.99/var/test/src/158-of-box.html/9/";
$lnk= preg_replace_callback("#/\\d+/#",function($matches){return "/".(trim($matches[0],"/")+1)."/";},$lnk); // http://99.99.99.99/var/test/src/158-of-box.html/10/
Basically, the regexp will capture a pure integer number enclosed by slashes, pass it along to the callback function which will purge the integer value, increment it, then return it for replacement with padded slashes on each side.
I'd suggest also another approach based on explode and implode instead of doing any regexp stuff. In my opinion this is more readable.
$str_value = "http://99.99.99.99/var/test/src/158-of-box.html/11/";
// explode the initial value by '/'
$explodedArray = explode('/', $str_value);
// get the position of the page number
$targetIndex = count($explodedArray) - 2;
// increment the value
$explodedArray[$targetIndex]++;
// implode back the original string
$new_str_value = implode('/', $explodedArray);

preg_replace with a word in an array

I am trying to use certain words in a array called keywords, which will be used to be replaced in a string by "as".
for($i = 0; $i<sizeof($this->keywords[$this->lang]); $i++)
{
$word = $this->keywords[$this->lang][$i];
$a = preg_replace("/\b$word\b/i", "as",$this->code);
}
It works with if I replace the variable $word with something like /\bhello\b/i, which then would replace all hello words with "as".
Is the approach am using even possible?
Before to be a pattern, it's a double quoted string, so variables will be replaced, it's not the problem.
The problem is that you use a loop to change several words and you store the result in $a:
the first iteration, all the occurences of the first word in $this->code are replaced and the new string is stored in $a.
but the next iteration doesn't reuse $a as third parameter to replace the next word, but always the original string $this->code
Result: after the for loop $a contains the original string but with only the occurences of the last word replaced with as.
When you want to replace several words with the same string, a way consists to build an alternation: word1|word2|word3.... It can easily be done with implode:
$alternation = implode('|', $this->keywords[$this->lang]);
$pattern = '~\b(?:' . $alternation . ')\b~i';
$result = preg_replace($pattern, 'as', $this->code);
So, when you do that, the string is parsed only once and all the words are replaced in one shot.
If you have a lot of words and a very long string:
Testing a long alternation has a significant cost. Even if the pattern starts with \b that highly reduces the possible positions for a match, your pattern will have hard time to succeed and more to fail.
Only in this particular case, you can use this another way:
First you define a placeholder (a character or a small string that can't be in your string, lets say §) that will be inserted in each positions of word boundaries.
$temp = preg_replace('~\b~', '§', $this->code);
Then you change all the keywords like this §word1§, §word2§ ... and you build an associative array where all values are the replacement string:
$trans = [];
foreach ($this->keywords[$this->lang] as $word) {
$trans['§' . $word . '§'] = 'as';
}
Once you have do that you add an empty string with the placeholder as key. You can now use the fast strtr function to perform the replacement:
$trans['§'] = '';
$result = strtr($temp, $trans);
The only limitation of this technic is that it is case-sensitive.
it will work if you keep it like bellow:
$a = preg_replace("/\b".$word."\b/i", "as",$this->code);

Get data out of string

I am going to parse a log file and I wonder how I can convert such a string:
[5189192e][game]: kill killer='0:Tee' victim='1:nameless tee' weapon=5 special=0
into some kind of array:
$log['5189192e']['game']['killer'] = '0:Tee';
$log['5189192e']['game']['victim'] = '1:nameless tee';
$log['5189192e']['game']['weapon'] = '5';
$log['5189192e']['game']['special'] = '0';
The best way is to use function preg_match_all() and regular expressions.
For example to get 5189192e you need to use expression
/[0-9]{7}e/
This says that the first 7 characters are digits last character is e you can change it to fits any letter
/[0-9]{7}[a-z]+/
it is almost the same but fits every letter in the end
more advanced example with subpatterns and whole details
<?php
$matches = array();
preg_match_all('\[[0-9]{7}e\]\[game]: kill killer=\'([0-9]+):([a-zA-z]+)\' victim=\'([0-9]+):([a-zA-Z ]+)\' weapon=([0-9]+) special=([0-9])+\', $str, $matches);
print_r($matches);
?>
$str is string to be parsed
$matches contains the whole data you needed to be pared like killer id, weapon, name etc.
Using the function preg_match_all() and a regex you will be able to generate an array, which you then just have to organize into your multi-dimensional array:
here's the code:
$log_string = "[5189192e][game]: kill killer='0:Tee' victim='1:nameless tee' weapon=5 special=0";
preg_match_all("/^\[([0-9a-z]*)\]\[([a-z]*)\]: kill (.*)='(.*)' (.*)='(.*)' (.*)=([0-9]*) (.*)=([0-9]*)$/", $log_string, $result);
$log[$result[1][0]][$result[2][0]][$result[3][0]] = $result[4][0];
$log[$result[1][0]][$result[2][0]][$result[5][0]] = $result[6][0];
$log[$result[1][0]][$result[2][0]][$result[7][0]] = $result[8][0];
$log[$result[1][0]][$result[2][0]][$result[9][0]] = $result[10][0];
// $log is your formatted array
You definitely need a regex. Here is the pertaining PHP function and here is a regex syntax reference.

regular expression to remove ID=1234 from a string (PHP)

I am trying to create a regular expression to do the following (within a preg_replace)
$str = 'http://www.site.com&ID=1620';
$str = 'http://www.site.com';
How would I write a preg_replace to simply remove the &ID=1620 from the string (taking into account the ID could be variable string length
thanks in advance
You could use...
$str = preg_replace('/[?&;]ID=\d+/', '', $str);
I'm assuming this is meant to be a normal URL, hence the [?&;]. If that's the case, the & should be a ?.
If it's part of a larger list of GET params, you are probably better off using...
parse_str($str, $params);
unset($params['ID']);
$str = http_build_query($params);
I'm guessing that & is not allowed as a character in the ID attribute. In that case, you can use
$result = preg_replace('/&ID=[^&]+/', '', $subject);
or (possibly better, thanks to PaulP.R.O.):
$result = preg_replace('/[?&]ID=[^&]+/', '', $subject);
This will remove &ID= (the second version would also remove ?ID=) plus any amount of characters that follow until the next & or end of string. This approach makes sure that any following attributes will be left alone:
$str = 'http://www.site.com?spam=eggs&ID=1620&foo=bar';
will be changed into
$str = 'http://www.site.com?spam=eggs&foo=bar';
You can just use parse_url
(that is if the URL is of the form: http://something.com?id1=1&id2=2):
$url = parse_url($str);
echo "http://{$url['host]}";

Php is stripping one letter "g" from my rtrim function but not other chars

I'm trying to trim some youtube URLs that I am reading in from a playlist. The first 3 work fine and all their URLs either end in caps or numbers but this one that ends in a lower case g is getting trimmed one character shorter than the rest.
for ($z=0; $z <= 3; $z++)
{
$ythref2 = rtrim($tubeArray["feed"]["entry"][$z]["link"][0]["href"], '&feature=youtube_gdata');
The URL is http://www.youtube.com/watch?v=CuE88oVCVjg&feature=youtube_gdata .. and it should get trimmed down to .. http://www.youtube.com/watch?v=CuE88oVCVjg but instead it is coming out as http://www.youtube.com/watch?v=CuE88oVCVj.
I think it may be the ampersand symbol but I am not sure.
The second argument to rtrim is a list of characters to remove, not a string to remove.
You might want to use str_replace, or use parse_url and parse_str to get arrays of the components of the URL and the components of the query string, like "v".
Untested example code:
$youtube_url = 'http://www.youtube.com/watch?v=CuE88oVCVjg&feature=youtube_gdata';
$url_bits = parse_url($youtube_url);
$query_string = array();
parse_str($url_bits['query'], $query_string);
$video_identifier = $query_string['v']; // "CuE88oVCVjg"
$rebuilt_url = 'http://www.youtube.com/watch?v=' . $video_identifier;
No, it's the g in the second argument. rtrim() does not remove a string from the end, it removes any characters given in the second argument. Use preg_replace() or substr() instead.

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