Code simplification for authorized chars only - php

I get a string that contains "#string.number (other stuff)".
I want to filter input from start+1 (= ignore the #) until I get something different than alphanumeric or '-', '_', '.'.
Here's my function:
function _isCharAllowed($c)
{
return (ctype_alnum(str_replace(array('-', '_', '.'), '', $c)));
}
$f=1;
while ($this->_isCharAllowed(mb_substr($str, $f, 1)))
$f++;
$key=mb_substr($str, 1, $f-2);
I want two things. First I have a problem with strings containing '-', '_', '.' because it doesn't do want I want: when there's such string, it removes those chars, giving empty string to ctype_alnum() which returns false:
php -r 'echo var_export((ctype_alnum("")), true)."\n";'
And I would like to optimize it.
How would you do?

You can replace them to an allowed character, say a. That way the string will never be empty.
Sidenote: I'm horrified (but not surprised) to hear that ctype_alnum("") returns false. It totally contradicts what the manual says... and the behaviour is even different in some versions: http://3v4l.org/IEtdi

Why not use preg_replace
Example:
$pattern = '/[^a-z0-9\-\_\.]/';
$strs = [
'some_string-with234.a',
'ano^ther-st*ring-with´+º~º'
];
foreach ($strs as $str) {
echo preg_replace($pattern, '', $str) . PHP_EOL;
}

Related

Remove all characters after last instance of particular character

How can I remove all the content in a string after the LAST occurance of a slash character / ?
For example, the string is:
http://localhost/new-123-rugby/competition.php?croncode=12345678
I want to remove all the content after the last / so that it just shows:
http://localhost/new-123-rugby/
But the content after the / could be of a variable length.
Please note, there could be any number of slashes in the URL. It needs to be able to remove content after the last slash. There could be more than shown in the example above.
you can try this
$url = "http://localhost/new-123-rugby/competition.php?croncode=12345678";
preg_match("/[^\/]+$/", $url, $matches);
$newUrl = str_replace($matches[0],'',$url);
echo $newUrl;
Solution #1, using substr() + strrpos():
$string = 'http://localhost/new-123-rugby/competition.php?croncode=12345678';
$pos = strrpos($string, '/');
if ($pos !== FALSE) {
echo(substr($string, 0, $pos + 1));
}
Function strrpos() finds the position of the last occurrence of / in the string, substr() extracts the required substring.
Drawback: if $string does not contain '/', strrpos() returns FALSE and substr() does not return what we want. Need to check the value returned by strrpos() first.
Solution #2, using explode() + implode():
$string = 'http://localhost/new-123-rugby/competition.php?croncode=12345678';
$array = explode('/', $string);
if (count($array) > 1) {
array_pop($array); // ignore the returned value, we don't need it
echo(implode('/', $array).'/'); // join the pieces back, add the last '/'
}
Alternatively, instead of array_pop($array) we can make the last component empty and there is no need to add an extra '/' at the end:
$string = 'http://localhost/new-123-rugby/competition.php?croncode=12345678';
$array = explode('/', $string);
if (count($array) > 1) {
$array[count($array) - 1] = ''; // empty the last component
echo(implode('/', $array)); // join the pieces back
}
Drawback (for both versions): if $string does not contain '/', explode() produces an array containing a single value and the rest of the code produces either '/' (the first piece of code) or an empty string (the second). Need to check the number of items in the array produced by explode().
Solution #3, using preg_replace():
$string = 'http://localhost/new-123-rugby/competition.php?croncode=12345678';
echo(preg_replace('#/[^/]*$#', '/', $string));
Drawbacks: none. It works well when both when $string contains '/' and it does not contain '/' (it does not modify $string in this case).
NOTA:
The question was edited so that the original answer (below the edit), doesn't match the requirements from OP. It wasn't marked as an edit from OP.
EDIT:
Updated my answer so it now matches the requirements of OP:
(Now it works with as many slashes as you want)
Will also work using
http://localhost/new-123-rugby////////competition.php?croncode=12345678
<?php
$url = "http://localhost/new-123-rugby/competition.php?croncode=12345678";
echo dirname($url) . "/";
?>
Output:
http://localhost/new-123-rugby/
Original answer:
This should work for you:
<?php
$string = "http://localhost/new-123-rugby/competition.php?croncode=12345678";
echo $string = substr($string, 0, strpos(strrev($string), "/")-2);
?>
Output:
http://localhost/new-123-rugby/
Demo: http://ideone.com/0R9QUG

PHP: preg_replace() to get "parent" component of NameSpace

How can I use the preg_replace() replace function to only return the parent "component" of a PHP NameSpace?
Basically:
Input: \Base\Ent\User; Desired Output: Ent
I've been doing this using substr() but I want to convert it to regex.
Note: Can this be done without preg_match_all()?
Right now, I also have a code to get all parent components:
$s = '\\Base\\Ent\\User';
print preg_replace('~\\\\[^\\\\]*$~', '', $s);
//=> \Base\Ent
But I only want to return Ent.
Thank you!
As Rocket Hazmat says, explode is almost certainly going to be better here than a regex. I would be surprised if it's actually slower than a regex.
But, since you asked, here's a regex solution:
$path = '\Base\Ent\User';
$search = preg_match('~([^\\\\]+)\\\\[^\\\\]+$~', $path, $matches);
if($search) {
$parent = $matches[1];
}
else {
$parent = ''; // handles the case where the path is just, e.g., "User"
}
echo $parent; // echos Ent
I think maybe preg_match might be a better choice for this.
$s = '\\Base\\Ent\\User';
$m = [];
print preg_match('/([^\\\\]*)\\\\[^\\\\]*$/', $s, $m);
print $m[1];
If you read the regular expression backwards, from the $, it says to match many things that aren't backslashes, then a backslash, then many things that aren't backslashes, and save that match for later (in $m).
How about
$path = '\Base\Ent\User';
$section = substr(strrchr(substr(strrchr($path, "\\"), 1), "\\"), 1);
Or
$path = '\Base\Ent\User';
$section = strstr(substr($path, strpos($path, "\\", 1)), "\\", true);

Replace all occurrences of \\ not starting with

This should be simple. I want to change all of these substrings:
\\somedrive\some\path
into
file://\\somedrive\some\path
but if substrings already have a file:// then I don't want to append it again.
This doesn't seem to do anything:
var_export( str_replace( '\\\\', 'file://\\\\', '\\somedrive\some\path file://\\somedrive\some\path' ) );
What am I doing wrong? Also, the above doesn't take into test for file:// already being there; what's the best way of dealing with this?
UPDATE test input:
$test = '
file://\\someserver\some\path
\\someotherserver\path
';
test output:
file://\\someserver\some\path
file://\\someotherserver\path
Thanks.
You should consider escape sequence in string also.
if((strpos($YOUR_STR, '\\\\') !== false) && (strpos($YOUR_STR, 'file://\\\\') === false))
var_export( str_replace( '\\\\', 'file://\\\\', $YOUR_STR ) );
Use a regular expression to check if the given substring starts with file://. If it does, don't do anything. If it doesn't, append file:// at the beginning of the string:
if (!preg_match("~^file://~i", $str)) {
$str = 'file://' . $str;
}
As a function:
function convertPath($path) {
if (!preg_match("~^file://~i", $path)) {
return 'file://'.$path;
}
return $path;
}
Test cases:
echo convertPath('\\somedrive\some\path');
echo convertPath('file://\\somedrive\some\path');
Output:
file://\somedrive\some\path
file://\somedrive\some\path
EDIT
For multiple occurrences : preg_replace('#((?!file://))\\\\#', '$1file://\\\\', $path)
This will work to give you the output you are expecting. As php.net says double slash will be converted into single slash.
if (!preg_match('/^file:\/\//', $str)) {
$str = "file://\\".stripslashes(addslashes($str));
}
Please try this:
$string = "\\somedrive\some\path";
$string = "\\".$string;
echo str_replace( '\\\\', 'file://\\\\',$string);

How to get everything after a certain character?

I've got a string and I'd like to get everything after a certain value. The string always starts off with a set of numbers and then an underscore. I'd like to get the rest of the string after the underscore. So for example if I have the following strings and what I'd like returned:
"123_String" -> "String"
"233718_This_is_a_string" -> "This_is_a_string"
"83_Another Example" -> "Another Example"
How can I go about doing something like this?
The strpos() finds the offset of the underscore, then substr grabs everything from that index plus 1, onwards.
$data = "123_String";
$whatIWant = substr($data, strpos($data, "_") + 1);
echo $whatIWant;
If you also want to check if the underscore character (_) exists in your string before trying to get it, you can use the following:
if (($pos = strpos($data, "_")) !== FALSE) {
$whatIWant = substr($data, $pos+1);
}
strtok is an overlooked function for this sort of thing. It is meant to be quite fast.
$s = '233718_This_is_a_string';
$firstPart = strtok( $s, '_' );
$allTheRest = strtok( '' );
Empty string like this will force the rest of the string to be returned.
NB if there was nothing at all after the '_' you would get a FALSE value for $allTheRest which, as stated in the documentation, must be tested with ===, to distinguish from other falsy values.
Here is the method by using explode:
$text = explode('_', '233718_This_is_a_string', 2)[1]; // Returns This_is_a_string
or:
$text = end((explode('_', '233718_This_is_a_string', 2)));
By specifying 2 for the limit parameter in explode(), it returns array with 2 maximum elements separated by the string delimiter. Returning 2nd element ([1]), will give the rest of string.
Here is another one-liner by using strpos (as suggested by #flu):
$needle = '233718_This_is_a_string';
$text = substr($needle, (strpos($needle, '_') ?: -1) + 1); // Returns This_is_a_string
I use strrchr(). For instance to find the extension of a file I use this function:
$string = 'filename.jpg';
$extension = strrchr( $string, '.'); //returns "jpg"
Another simple way, using strchr() or strstr():
$str = '233718_This_is_a_string';
echo ltrim(strstr($str, '_'), '_'); // This_is_a_string
In your case maybe ltrim() alone will suffice:
echo ltrim($str, '0..9_'); // This_is_a_string
But only if the right part of the string (after _) does not start with numbers, otherwise it will also be trimmed.
if anyone needs to extract the first part of the string then can try,
Query:
$s = "This_is_a_string_233718";
$text = $s."_".substr($s, 0, strrpos($s, "_"));
Output:
This_is_a_string
$string = "233718_This_is_a_string";
$withCharacter = strstr($string, '_'); // "_This_is_a_string"
echo substr($withCharacter, 1); // "This_is_a_string"
In a single statement it would be.
echo substr(strstr("233718_This_is_a_string", '_'), 1); // "This_is_a_string"
If you want to get everything after certain characters and if those characters are located at the beginning of the string, you can use an easier solution like this:
$value = substr( '123_String', strlen( '123_' ) );
echo $value; // String
Use this line to return the string after the symbol or return the original string if the character does not occur:
$newString = substr($string, (strrpos($string, '_') ?: -1) +1);

PHP substring extraction. Get the string before the first '/' or the whole string

I am trying to extract a substring. I need some help with doing it in PHP.
Here are some sample strings I am working with and the results I need:
home/cat1/subcat2 => home
test/cat2 => test
startpage => startpage
I want to get the string till the first /, but if no / is present, get the whole string.
I tried,
substr($mystring, 0, strpos($mystring, '/'))
I think it says - get the position of / and then get the substring from position 0 to that position.
I don't know how to handle the case where there is no /, without making the statement too big.
Is there a way to handle that case also without making the PHP statement too complex?
The most efficient solution is the strtok function:
strtok($mystring, '/')
NOTE: In case of more than one character to split with the results may not meet your expectations e.g. strtok("somethingtosplit", "to") returns s because it is splitting by any single character from the second argument (in this case o is used).
#friek108 thanks for pointing that out in your comment.
For example:
$mystring = 'home/cat1/subcat2/';
$first = strtok($mystring, '/');
echo $first; // home
and
$mystring = 'home';
$first = strtok($mystring, '/');
echo $first; // home
Use explode()
$arr = explode("/", $string, 2);
$first = $arr[0];
In this case, I'm using the limit parameter to explode so that php won't scan the string any more than what's needed.
$first = explode("/", $string)[0];
What about this :
substr($mystring.'/', 0, strpos($mystring, '/'))
Simply add a '/' to the end of mystring so you can be sure there is at least one ;)
Late is better than never. php has a predefined function for that. here is that good way.
strstr
if you want to get the part before match just set before_needle (3rd parameter) to true
http://php.net/manual/en/function.strstr.php
function not_strtok($string, $delimiter)
{
$buffer = strstr($string, $delimiter, true);
if (false === $buffer) {
return $string;
}
return $buffer;
}
var_dump(
not_strtok('st/art/page', '/')
);
One-line version of the accepted answer:
$out=explode("/", $mystring, 2)[0];
Should work in php 5.4+
This is probably the shortest example that came to my mind:
list($first) = explode("/", $mystring);
1) list() will automatically assign string until "/" if delimiter is found
2) if delimiter "/"is not found then the whole string will be assigned
...and if you get really obsessed with performance, you may add extra parameter to explode explode("/", $mystring, 2) which limits maximum of the returned elements.
The function strstr() in PHP 5.3 should do this job.. The third parameter however should be set to true..
But if you're not using 5.3, then the function below should work accurately:
function strbstr( $str, $char, $start=0 ){
if ( isset($str[ $start ]) && $str[$start]!=$char ){
return $str[$start].strbstr( $str, $char, $start+1 );
}
}
I haven't tested it though, but this should work just fine.. And it's pretty fast as well
You can try using a regex like this:
$s = preg_replace('|/.*$|', '', $s);
sometimes, regex are slower though, so if performance is an issue, make sure to benchmark this properly and use an other alternative with substrings if it's more suitable for you.
Using current on explode would ease the process.
$str = current(explode("/", $str, 2));
You could create a helper function to take care of that:
/**
* Return string before needle if it exists.
*
* #param string $str
* #param mixed $needle
* #return string
*/
function str_before($str, $needle)
{
$pos = strpos($str, $needle);
return ($pos !== false) ? substr($str, 0, $pos) : $str;
}
Here's a use case:
$sing = 'My name is Luka. I live on the second floor.';
echo str_before($sing, '.'); // My name is Luka
$arr = explode("/", $string, 2); $first = $arr[0];
This Way is better and more accurate than strtok
because if you wanna get the values before # for example
while the there's no string before # it will give you whats after the sign .
but explode doesnt
$string="kalion/home/public_html";
$newstring=( stristr($string,"/")==FALSE ) ? $string : substr($string,0,stripos($string,"/"));
why not use:
function getwhatiwant($s)
{
$delimiter='/';
$x=strstr($s,$delimiter,true);
return ($x?$x:$s);
}
OR:
function getwhatiwant($s)
{
$delimiter='/';
$t=explode($delimiter, $s);
return ($t[1]?$t[0]:$s);
}

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