How To Validate Email Addresses Using Regular Expressions

Hello friends today i am telling you how to validate Email addresses using Regular Expressions.I hope you all are aware of Regular expressions,you have a little knowledge about Regular Expressions before reading this article.If you don't know anything about it then click this link.

Regular Expression Tutorials

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Now try to understand the following validation process.

Before validating Email address you have to know something about it.

The local-part (the part before the "@" character) of the e-mail may use any of these ASCII characters:

• Uppercase and lowercase letters
• The digits 0 through 9
• The characters , ! # $ % & ' * + - / = ? ^ _ ` { | } ~
• The character "." provided that it is not the first or last character in the local-part

The domain part of the address is much easier to handle. The dot separated domain labels can only include letters, digits and hyphens.

Regular Expression is:

^[a-z 0-9_\+-]+(\.[a-z 0-9_\+-]+)*@[a-z 0-9-]+(\.[a-z 0-9-]+)*\.([a-z]{2,4})$

Explanation:-

The first part,^[a-z 0-9_\+-]+ means that the address has to start with letters a-z, numbers 0-9 or characters "_", "+" or "-" The final "+" means there must be 1..n of these characters.For example:learning12,doon+123 etc.

The regexp continues with (\.[a-z 0-9_\+-]+)* . It means that the first characters defined before can be followed with a period "." and after that with the same set of characters than before the period. Because characters "." and "+" have special meaning in regexps they must be escaped with a backslash. The final * means there must be 0..n of these sequences.For example: doon.geu+edu

After these characters there must be a single "@" character. It must be followed by a domain label that consist of letters, numbers and hyphens. There can be 1..n domain labels separated with a period. The first label (without the period) is defined by [a-z 0-9-]+ After this there can be 0..n similar sequences starting with a period. This is defined as (\.[a-z 0-9-]+)*

\.([a-z]{2,4})$ means at the end string is followed by 2..4 letters.

Also see this:

• What Is Mail Merge?

• Create a Windows e-mail Shortcut

***Thanks Friends***