Can you please explain email regex in UiPath matches activity?

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We can find the following email address regex in UiPath string matches activity.

((?>[a-zA-Z\d!#$%&'+-/=?^_{|}~]+\x20*|"((?=[\x01-\x7f])[^"\\]|\\[\x01-\x7f])*"\x20*)*(?<angle><))?((?!\.)(?>\.?[a-zA-Z\d!#$%&'*+\-\/=?^_{|}~]+)+|“((?=[\x01-\x7f])[^”\]|\[\x01-\x7f])")@(((?!-)[a-zA-Z\d-]+(?<!-).)+[a-zA-Z]{2,}|[(((?(?<![).)(25[0-5]|2[0-4]\d|[01]?\d?\d)){4}|[a-zA-Z\d-]*[a-zA-Z\d]:((?=[\x01-\x7f])[^\]|\[\x01-\x7f])+)])(?(angle)>)

This regex looks too complex for me. I’ve not seen this much complex regex for email extraction. Can someone please explain this regex in detail or do we have any website/documenation explaining this part by part?

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@Surya_Narayana_Korivipadu - Since this regex can cover all the variations it was complex…

Please check this page where you can get easy to very complex one…

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Hi @Surya_Narayana_Korivipadu

It is complex code since it is trying every type of email address which comes in different format

Regards

Nived N :robot:

Happy Automation :relaxed::relaxed::relaxed:

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@Surya_Narayana_Korivipadu

Pleas have a look

1340×1040 120 KB

This is a rail road diagram for above regex.
This explain or & and cases and how they are formed.
Hope this will help you understand logic

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Thank you for the comment. Now I’ve got a little bit understanding about the characters checked by this regex. But there are still many parts of the regex which I’m not able to understand. Where can I get part by part explanation which can help me understand and build this regex by myself?

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Ok. I’ll check this

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@Surya_Narayana_Korivipadu
Use this website, It will give you brief explanation to each form used

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@Surya_Narayana_Korivipadu …Yes …give me your sample email addresses …will share the some simple regex pattern …

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Thank you. This website is helping me. This is giving detailed explanation about every part of this regex.

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No. I don’t have any use case. I’m just trying to understand how UiPath built this regex.

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@Surya_Narayana_Korivipadu - Uipath doesn’t build regex…you have to code your pattern and use it on the UiPath…

Please take a look at the post where Regex pattern provided to fetch various amounts…

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In the string matches activity “Configure Regular Expression” , this email regex was available by default. I’m referring to that one. Anyways, I’ve found a way to understand this from @Lakshay_Verma comments. Thank you.

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I use 2 regex patterns:

Very simple:

^[_a-z0-9-]+(.[a-z0-9-]+)@[a-z0-9-]+(.[a-z0-9-]+)*(.[a-z]{2,4})$

Complex (RFC 5322):

^(?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9]))\.){3}(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9])|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])$

Interesting sources:

RFC822

http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html

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