Replacing&extracting an item in a string

Hey guys i think i must be missing something. Trying to do this with less code possible

Was looking over string functions in the manual but i dont see anything that does what im trying to do.

$string = "hey whats up @sam how are you doing";

I'm wanting to replace @sam with

<a href='' class='profile_name' id='$name>$name</a>

is there a way to extract @sam so i can get rid of the @ then place the name into the link $name

the only thing i can find is finding the location of @ using strpos but im not sure how to extract only the letters attached to @ and nothing else in the string

only way i can think about doing it is to extract everything after @ then exploding it by spaces with a limit of 1

is that the best way to do this?

Try using a regular expression to match the at symbol followed by any characters [edit: plural] that aren't a space followed by a space:

/@([^\s]+)\s/

Use this with a function like preg_match to find the name. Note that the brackets around the part between the @ and the following space indicate a part you wish to save for use.

thanks for the responce Tarential

expressions are like a dark art to me lol

Thanks alot it works.

i'll go ahead and just submit my code incase someone else reads this to help them out.

$string = "hey whats up @sam how are you doing";

if (preg_match('/@([^\s]+)\s/', $string, $name)) { 	

	print_r($name);

}

Either use regular expression or use the str_replace() function.  That takes a search term, a replacements term and the string you want to work on.

I've heard it's quicker than using preg_replace with regex but it's probably such a nominal difference that it's not worth worrying about.

Either use regular expression or use the str_replace() function.  That takes a search term, a replacements term and the string you want to work on.

 

I've heard it's quicker than using preg_replace with regex but it's probably such a nominal difference that it's not worth worrying about.

 

The difference in speed is huge, but str_replace will only match static data. Regular expressions allow for patterns to be found.

Ahh well there you go

And yeah I would favour regex if looking for something dynamic but the post seemed to suggest @sam was the term - so maybe i misread

Either use regular expression or use the str_replace() function.  That takes a search term, a replacements term and the string you want to work on.

 

I've heard it's quicker than using preg_replace with regex but it's probably such a nominal difference that it's not worth worrying about.

 

 

The difference in speed is huge, but str_replace will only match static data. Regular expressions allow for patterns to be found.

ya the name is dynamtic

im confused on how i would use preg_replace. How would i get the variable $name filled in this link with sam using preg_replace instead of preg_match? You saying this could be done in one line of code xyph?

<a href='' class='profile_name' id='$name>$name</a>

$string = "hey whats up @sam how are you doing";

if (preg_match('/@([^\s]+)\s/', $_POST['message'], $name)) { 	

	print_r($name);

}

I believe he was suggesting using preg replace on a regex like this to cut out everything except the matching string:

/^.*@([^\s]+)\s.*$/

Probably not the most efficient way of doing it but it works...

$string = "hey whats up @sam how are you doing";

$pattern = '/@[a-zA-Z]+/';

 preg_match($pattern, $string, $matches);

$name =  substr($matches[0], 1);



$stringtwo = "<a href='' class='profile_name' id='name'>$name</a>";


//$string contains new string with link changed to name dynamically
$string = str_replace($matches[0], $stringtwo, $string);

when I use the code im using now the return of the array is

Array ( [0] => @sam[1] => sam)

so im already getting just the name

how would i go about changing it so its looking for "  @" instead of "@"

this way people can still type email address's and it will ignore it

Just need to change the pattern to:

'/\s@[a-zA-Z]+/';

Oh and add a space before $name in $stringtwo

$stringtwo = "<a href='' class='profile_name' id='name'> $name</a>";

how would i go about changing it so its looking for "  @" instead of "@"

 

this way people can still type email address's and it will ignore it

OH and you'd also have to change

$name =  substr($matches[0], 2);

Because now it needs to look two characters from the start instead of one. Then it should all work again!

Adding "\s" in front of the @ symbol in the regex is the correct way to include a space in the match. Then, assuming you used my code, you would reference $matches[1] (not $matches as a whole, which is an array, or $matches[0], which is the entire string match). $matches[1] is what contains "sam" in the array you posted.

The manual provides details on how to do this is preg_replace. I'm not sure why I need to post an example as well.

Also \s is the correct way to match a white-space character. A literal space, or one preceded by a backslash in the case of free-spacing, is the correct way to match a space.

<?php

$string = 'hello @sam nice to meet you';

$match = '/@([^\s]+)/';
$replace = '<a href="page.php?name=$1">$1</a>';

echo preg_replace($match, $replace, $string);

?>

Tarential: No need to bind the RegExp to the start and end of the string. We're not talking about validating the entire string, but just looking to grab a little subset of it.

Shadowing: To sum up this little thread, what you'll need is something that looks like this:

$string = "hey what's up @sam how are you doing?";
$replace = ' <a href="" class="profile_name" id="$1">$1</a>';
echo preg_replace ("/\\s@(\\S+)/u", $replace, $string);

Double escaping since "\" is a meta-character in PHP strings. "\\S" is the same as "[^\\s]+", only with less typing. Also using the "u" modifier to make it UTF-8 compatible. Also, added a space in front of the anchor-tag, to replace the one we're removing in the RegExp.

Tarential: No need to bind the RegExp to the start and end of the string. We're not talking about validating the entire string, but just looking to grab a little subset of it.

 

Shadowing: To sum up this little thread, what you'll need is something that looks like this:

$string = "hey what's up @sam how are you doing?";
$replace = ' <a href="" class="profile_name" id="$1">$1</a>'
echo preg_replace ("/\\s@(\\S+)/u", $string, $replace);

 

Double escaping since \ is a meta-character in PHP strings. "\\S" is the same as "[^\\s]+", only with less typing. Also using the "u" modifier to make it UTF-8 compatible.

You should test your code.

Yeah, noticed it right after posting. Changed it while you were posting.

Out of interest so i understand this patttern (as my regex is a bit rusty):

$match = '/@([^\s]+)/';

This pattern says:  find instance of '@' then match anything that isn't a space after the @? Tis very clever if that's the case - regex really is quite something.

Yep, that's exactly what it says. With the added bit of storing that "everything that isn't a space" in a sub group, which is then referenced to by the "$1" in the replacement string.

RegExp sure is great, but easily abused and can get really complex really fast. So take heed when using it.

Yeah, noticed it right after posting. Changed it while you were posting.

What about

$string = "@sam loves po-ta-toes";

Out of interest so i understand this patttern (as my regex is a bit rusty):

 

$match = '/@([^\s]+)/';

 

This pattern says:  find instance of '@' then match anything that isn't a space after the @? Tis very clever if that's the case - regex really is quite something.

You've got it. The + means 1 or more times, and the brackets capture the result to be used later.

So, it has to be an @ followed by one or more characters than aren't spaces.

What about

$string = "@sam loves po-ta-toes";

Seems we both missed out on something:

how would i go about changing it so its looking for "  @" instead of "@"

 

this way people can still type email address's and it will ignore it

Though, I should indeed have thought about the possibility of the search term being the first word in the string. I shall fix that right away.

Addendum:

Hmm.... Seems I can't go back and edit my post any more. Oh, well. Here's the updated version:

$string = "@Christian is testing!";
$replace = '$1<a href="" class="profile_name" id="$2">$2</a>';
echo preg_replace ("/((?<!\\S))@(\\S+)/u", $replace, $string);

(?:^|\s)@(\S+)

Make that sub group capturing, and we agree.