Extracting all Email Ids in any given String using Regular Expressions

Given a string str, the task is to extract all the Email ID's from the given string.

Example:

Input: "Please send your resumes to Hr@Iwillgetbacktoyou@gmail.com for any business inquiry please mail us at business@enquiry@gmail.com"
Output: Hr@Iwillgetbacktoyou@gmail.com
business@enquiry@gmail.com

Approach: The problem can be solved based on the following idea:

Create a regex pattern to validate the number as written below:   
regex = “^[0-9]{3}[A-Z]{2}[0-9]{8}$“

Where,

• $: Matches the end of the line
• \s: Matches whitespace
• \S: Matches any non-whitespace character
• *: Repeats a character zero or more times
• \S: Matches any non-whitespace character
• *?: Repeats a character zero or more times (non-greedy)
• +: Repeats a character one or more times
• +?: Repeats a character one or more times (non-greedy)
• [aeiou]: Matches a single character in the listed set
• [^ABC]: Matches a single character, not in the listed set
• [a-z0-9]: The set of characters can include a range
• (: Indicates where string extraction is to start
• ): Indicates where string extraction is to end

Follow the below steps to implement the idea:

• Create a regex expression to extract all the Email Ids from the string.
• Use Pattern class to compile the regex formed.
• Use the matcher function to find.

Below is the code implementation of the above-discussed approach:

Hr@Iwillgetbacktoyou@gmail.com
business@enquiry.com

Time Complexity: O(n)

Space Complexity: O(n)

Related Articles:

• Regular Expressions in Java
• Python RegEx
• JavaScript Regular Expressions