PHP - Regex. Replace any space in quote with underscore?

Question

regex noob hear. Via PHP and preg_replace()...

I'm trying to make this.

id="New York State"

Into this.

id="New_York_State"

But not this.

id="New_York_State"_class="United_States"

All my attempts have been abysmal!
I've read several tutorials but I am still having a lot of trouble formulating useful patterns with correct syntax.

Please, please, please, include a explanation of the regex pattern with your answer! Also, if you feel up to it, any links to good PHP regex tutorials or articles would be much appreciated. Thanks!

I think the best way to do this is using DOM, check for all classes and id's and do a space replacement. — HamZa
– HamZa, Commented May 11, 2013 at 21:01
@Terry just curious: you know that class="United States" has a different meaning than class="United_States"? — crackmigg
– crackmigg, Commented May 11, 2013 at 21:33

Baba · Accepted Answer · 2013-05-11 21:37:57Z

4

Use SimpleXMLElement

header('Content-Type:text/plain');
$xml = simplexml_load_file('log.svg', "SimpleXMLElement");
recursiveReplace($xml);
echo $xml->asXML();

Function Used

function recursiveReplace(&$xml) {
    foreach($xml as $k => $value) {
        foreach($xml->attributes() as $n => $d) {
            $xml[$n] = preg_replace('/\s+/', '_', $d);
        }
        recursiveReplace($value);
    }
}

answered May 11, 2013 at 21:37

Baba

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2 Comments

HamZa Over a year ago

Was waiting for the canonical answer :D

Terry Over a year ago

@Baba This seems like a very elegant and approachable solution. I'm working on a WAMP environment, it seems that I need to install a few libraries to be able to use the SimpleXMLElement extension. Not a problem but I was really just looking for a regex pattern. Still super usefull, thank you. Really appreciate it!

HamZa · Accepted Answer · 2013-05-11 21:08:27Z

3

An extremely bad solution:

$string = 'blabla id="New_York_State" class="United_States" blabla';

$new_string = preg_replace_callback('#\"([^"]*)\"#', function($m){
    return('"'. str_replace(' ', '_', $m[1]) .'"');
}, $string);
echo $new_string;

Output:

blabla id="New_York_State" class="United_States" blabla

Allowing only id= and class= behind the double quotes:

$string = 'blabla id="New_York_State" class="United_States" blabla "this won\'t get underscored" yaaaay';

$new_string = preg_replace_callback('#(?<=id=|class=)\"([^"]*)\"#', function($m){
    return('"'. str_replace(' ', '_', $m[1]) .'"');
}, $string);
echo $new_string;

Output:

blabla id="New_York_State" class="United_States" blabla "this won't get underscored" yaaaay

answered May 11, 2013 at 21:08

HamZa

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7 Comments

Terry Over a year ago

To tell you the truth I wouldn't know how to do this through the DOM with PHP. Currently I have been loading the <svg> into a browser making applicable changes with JavaScript and copying the <svg> via firebug to a text editor O_o (eye twitch)

Terry Over a year ago

I'm NOT a programmer. I'm a graphic design student teaching himself to code. I understand most of the regexp pattern, except... ?<=, and meaning of * in ([^"]*).

HamZa Over a year ago

@Terry I'm a nobody and I learnt from here and there, but don't worry I'll explain :) (?<=) is a lookbehind assertion for example (?<=a)b this will match b if there is a before it: ab the b here gets matched acb the b here doesn't get matched. * is basically 0 or more times, [] means a character class, so [^"] will match anything but " we add * to it to match several characters if possible [^"]*, so for example this will match abc in abc".

Terry Over a year ago

You are not a nobody. Don't say that. Thank you for your help, it was a great explanation,

HamZa Over a year ago

@Terry haha you're welcome, also you may try regex101 which is a good site to test your regex and also get a bit of explanation on it and you may take a look at this tutorial, have fun !

|

g2236670 · Accepted Answer · 2013-05-11 21:28:28Z

0

There is a function called str_replace.

Your code will be like this:

$id = str_replace(" ", "_", $id); or better $id = str_replace("New York State", "New_York_State", $id);

Source: http://php.net/manual/en/function.str-replace.php

edited May 11, 2013 at 21:28

answered May 11, 2013 at 21:00

g2236670

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3 Comments

HamZa Over a year ago

Actually this information is true, but it doesn't answer this particular question.

Tim Pietzcker Over a year ago

This will replace all spaces, not just those within id attributes.

Casimir et Hippolyte Over a year ago

If you use it with the DOM, why not.

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