Python Regex For Email Addresses, Need To Weed Out Dot Dash

I have created this regular expression to weed out obviously wrong email addresses. For my large data set it works for 98% of cases. pattern = re.compile('^([a-zA-Z0-9._-]+)([a-zA

Solution 1:

You can use negative look ahead assertion here

^(?!.*\.-.*$|.*-\..*$)([a-zA-Z0-9._-]+)([a-zA-Z0-9]@[a-zA-Z0-9])([a-zA-Z0-9.-]+)([a-zA-Z0-9]\.[a-zA-Z]{2,3})$

Regex explanation here

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More specific one will be

^(?![a-zA-Z0-9._@-]*\.-[a-zA-Z0-9._@-]*$|[a-zA-Z0-9._-@]*-\.[a-zA-Z0-9._-@]*$)([a-zA-Z0-9._-]+)([a-zA-Z0-9]@[a-zA-Z0-9])([a-zA-Z0-9.-]+)([a-zA-Z0-9]\.[a-zA-Z]{2,3})$

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Or in case .., --, ..., etc. are not allowed then you can use

^(?![a-zA-Z0-9._@-]*[.-]{2,}[a-zA-Z0-9._@-]*$)([a-zA-Z0-9._-]+)([a-zA-Z0-9]@[a-zA-Z0-9])([a-zA-Z0-9.-]+)([a-zA-Z0-9]\.[a-zA-Z]{2,3})$