如何在 PHP 中使用 preg_match() 以相反的顺序从一堆文本中获取特定字符串

Question

Currently I am using below code for getting specific string from the texts.

preg_match('~background(.*?).png~', $css_content, $output);

I use this code for getting specific text from bunch of the text. This code works but it goes serially that is left to right.
For example: Let's say following of texts

"color:#fff; background:url('assets/imgages/background.png');"

Now I want to get text " background:url('assets/images/background.png "
The function preg_match() works like this:
It first finds the "background" text that I've added in above function then it finds for ".png" text also added in function. This looks like it works left to right. But I want to make it opposite that is right to left.
What I want to do is, function should find ".png" first and then it should be go for "background" text.

Answer 1

You can use so called positive look ahead .

~(background...(?=\\.png)~

-> finds the background (if .png is after it)

In your situation:

preg_match('~background(.*?)(?=\.png)~', $css_content, $output);

You can test it here:

https://regex101.com/r/kC2rO2/1