How does PHP extract a url from a text segment?

How does PHP extract a url from a paragraph of text? Which methods can be used to extract URLs from a file? what is the best method ?, It depends on the construction of your url. I. Regular expression 2. dom elements can be converted. how can PHP extract a url from a text segment based on the url attribute?
Which methods can be used to extract URLs from a file? what is the best method?

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It depends on the construction of your url. 1. you can use regular expression 2 to convert dom elements and obtain url attributes.