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This document provides instructions for validating email addresses using a regular expression. An email address is considered valid if it meets the following criteria: 1. The user name starts with 1-6 lowercase English letters. 2. The letters can be followed by an optional underscore. 3. The underscore (if present) can be followed by 0-4 optional digits. The document includes sample code and test cases to validate email addresses against these criteria using a regular expression. It provides an example of a valid email address and explains why two invalid addresses fail the criteria.

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1K views1 page

Hacker Rank

This document provides instructions for validating email addresses using a regular expression. An email address is considered valid if it meets the following criteria: 1. The user name starts with 1-6 lowercase English letters. 2. The letters can be followed by an optional underscore. 3. The underscore (if present) can be followed by 0-4 optional digits. The document includes sample code and test cases to validate email addresses against these criteria using a regular expression. It provides an example of a valid email address and explains why two invalid addresses fail the criteria.

Uploaded by

IPhone Apple
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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11/26/2019 HackerRank

2m 20s Python 3 Autocomplete Ready


left
1 #!/bin/python3 ⋯
4. Validating Email Addresses with RegEx 7  
ALL
8 #
9 # Write the regular expression in the blank space below
In this question, we consider an email address in the form user@domain.extension to be 10 #
 valid if its domain and extension are hackerrank.com and the value of user satisfies the 11 regularExpression = '________'
following constraints: 12 pattern = compile(regularExpression) ⋯
1
It starts with between 1 and 6 lowercase English letters denoted by the character class [a-
z].
2 The lowercase letter(s) are followed by an optional underscore, i.e. zero or one occurrence
of  the _ character.
The optional underscore is followed by 0 to 4 optional digits denoted by the character
3
class [0-9]. 

4 Complete the code in the editor below by replacing the blank ("________") with a regular
expression that matches valid email addresses according to the criteria above. Locked
code in the editor prints True for each correct match and False for each incorrect match.
5
An example of a valid email is abcdef_1234@hackerrank.com.  It has as many of each
class of character as possible.  The address a1_1@baddomain.com fails for two reasons. 
6 First, digits cannot precede the underscore.  Second, the domain fails because it is not
hackerrank.

7 Constraints

1 ≤ query ≤ 103
8
1 ≤ string length ≤ 103. Line: 7 Col: 1

9 Input Format Test Results Custom Input Run Submit Code

10
Sample Case 0

11 Sample Input 0

5
12
julia@hackerrank.com
julia_@hackerrank.com
13 julia_0@hackerrank.com
julia0_@hackerrank.com
julia@gmail.com
14

Sample Output 0
15
True
True
True
False
False

Explanation 0

We perform the following query = 5 validations:

1. julia@hackerrank.com starts with between 1 and 6 lowercase letters and contains zero of
the optional characters, so it's valid.
2. julia_@hackerrank.com starts with between 1 and 6 lowercase letters, is followed by a
single underscore, and contains none of the optional digits, so it's valid.
3. julia_0@hackerrank.com starts with between 1 and 6 lowercase letters, is followed by a
single underscore, and is followed by between 0 and 4 digits, so it's valid.
4. julia0_@hackerrank.com has valid lowercase letters followed by a valid digit, but the digit
must not precede the underscore.
5. julia@gmail.com has a valid user name, but its domain and extension do not
match hackerrank.com.

https://www.hackerrank.com/test/7ra6fpm5mrq/questions/c8276ohcpl 1/1

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