What is an effective way to find a pattern in large text?

Question

I want to extract email addresses from a large text file. What is the best way to do this?

My idea is to find the '@' in the text and use "Regex" to find the email address in the substring (for example) 256 characters before this position and 512 in length.

PS: Right, I want to know the best and most effective way to find some kind of template (for example, email addresses) in a huge text.

Answer 1

256 and 512 sound like arbitrary values.

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64 255 .

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Answer 2

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[A-Za-z0-9!#$%&*+-=?^_~]{1,64}@[A-Za-z0-9-.]{1,255}\.[A-Z]{2,6}

Answer 3

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Answer 4

, RFC . , - :

/(?<=^|[\s<(\["'])[a-z][\w.+-]+@[\w-]+(?:\.[\w-]+)+(?=[>)\]"']|$)/gi

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