How to read all numeric values from within a file in php?

Question

I have a CSS file with numeric values with appending px like "width: 500px;". I need to read this file from start to end using php and alter all numeric values wherever found .i.e. convert 500px to some thing else like 50% of it (width: 250px). How can we do this, maybe using regex.

$file = fopen("file.css", "r+") or exit("Unable to open file!");
while(!feof($file))
{
if(numeric value between space and px)
//replace by its 50%
}
fclose($file);

This code is just to explain problem, solution can be entirely different.

You can probably just use php to change text in your css. Using a mycss.php file will get you variables which may be more reliable and faster than parsing with replacements. That is if this isn't a one time thing. If you need to change these values often I recommend a php file. — Quentin Engles
– Quentin Engles, Commented Feb 28, 2014 at 8:12

Toto · Accepted Answer · 2014-02-28 08:43:36Z

1

Use preg_replace_callback:

$str = preg_replace_callback('/:\s*(\d+)px/', 
    function($m) {
        return ': '.($m[1]/2).'px';
    },
    $str);

answered Feb 28, 2014 at 8:43

Toto

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2 Comments

Robin Over a year ago

Why do you need the px? \b\d+ would select all numbers just fine including em etc...

Toto Over a year ago

@Robin: OP wants to convert values in px only.

Community · Accepted Answer · 2017-05-23 12:28:44Z

0

The regex you are probably looking for is

^[\d]*(\.\d*)?(px)?(%)?(em)?$

or without decimal values

^[\d]*(px)?(%)?(em)?$

This should match all the sizes.. If you want also colors (RGB/RGBA format) then take a look at this question which might inspire you.

edited May 23, 2017 at 12:28

CommunityBot

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answered Feb 28, 2014 at 7:50

Dropout

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2 Comments

Dropout Over a year ago

Wait, need to take into account decimal numbers.. I will update it soon.

Robin Over a year ago

The [...] are useless around \d, which is already a shortcut for [0-9].

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