Regex for az, 0-9 ,. and -

Question

Can someone tell me which syntax for the regular expression will consist only of the following characters:

• az (lowercase only)
• 0-9
• period, dash, underline

In addition, the string must begin with a lowercase letter (az) and cannot contain spaces or other characters than those listed above.

Thanks in advance for your help, Justin

Answer 1

You can do: "^[az][-a-z0-9\._]*$"

Here is a breakdown

• ^ start of line
• [az] character class for lower values ​​to match the first letter
• [-a-z0-9\._] character class for the rest of the required value
• * zero or more for the last class
• $ end of line

Answer 2

 [-._a-z0-9] 

or

 [-.[:lower:][:digit:]] 

or...

depends on which version of regular expressions you are striving for.

Answer 3

 ^[az][a-z0-9._\s-]*