使用正则表达式验证用户名

Question

1. The only numbers in the username have to be at the end. There can be zero or more of them at the end.

2. Username letters can be lowercase and uppercase.

3. Usernames have to be at least two characters long. A two-letter username can only use alphabet letter characters.

I'm trying with this but I'm stalled. /\\d+$\\w+/gi

Answer 1

/^[az]{2,}\\d*$/i is:

^     : the begining
[a-z] : a character (a to z), you can add as many allowed characters as you want
{2,}  : at least 2 of them
\d*   : 0 or more digits 
$     : the end
i     : ignore case sensetivity (both lowercases and uppercases are allowed)

Answer 2

Username having characters and digit and min 2 character long

/^[a-zA-Z]{2,}\d*$/i

Test result :

UserNam9 = pass
9username = fail
Userna99 = pass
usernameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee = pass
Us = pass
U = fail

Answer 3

/^[A-z]{2,}[A-z0-9]{0,}$/
/^ // start of line
[A-z]{2,} //alphabet characters 2 or more
[A-z0-9]{0,} //numbers and alphabet 
$/ // end of line

Answer 4

You've missed cases when there's a letter in the start, followed by 2 or more numbers.

U99 = fail
d345 = fail

My solution passes these tests, as well:

/^[a-z]{2,}\d*$|(?=\w{3,})^[a-z]{1,}\d+$/i

Using positive lookahead I am making sure that in the second case there are at least 3 alphanumeric characters.

Answer 5

Simplified version of /^[az]{2,}\\d*$|(?=\\w{3,})^[az]{1,}\\d+$/i :

/^\D(\d{2,}|\D+)\d*$/i

Code explanation:

1. ^ - start of input
2. \\D - first character is a letter
3. \\d{2,} - ends with two or more numbers
4. | - or
5. \\D+ - has one or more letters next
6. \\d* - and ends with zero or more numbers
7. $ - end of input
8. i - ignore case of input

Answer 6

This is my answer, it passed all the tests:

/^[a-z][a-z]+\d*$|^[a-z]\d{2,}$/i

• First Part: 2 letters (or more) and zero or more numbers
• Or
• Second Part: 1 letter and 2 or more numbers