Regex - At least one alphanumeric character and allow spaces

Question

I want to make sure a first name field has at least one alphanumeric character and also allow spaces and dashes.

**VALID**

David
Billie Joe
Han-So

**INVALID**
-

Empty is also invalid

Answer 1

use this pattern

^(?=.*[a-zA-Z])[a-zA-Z -]+$  

Demo

oh, for alphanumeric use

^(?=.*[a-zA-Z0-9])[a-zA-Z 0-9-]+$ 

Answer 2

To ensure the dashes and spaces happen in legitimate places, use this:

(?i)^[a-z]+(?:[ -]?[a-z]+)*$

See demo .

• (?i) puts us in case-insensitive mode
• ^ ensures we're at the beginning of the string
• [az]+ matches one or more letters
• [ -]?[az]+ matches an optional single space or dash followed by letters...
• (?:[ -]?[az]+)* and this is allowed zero or more times
• $ asserts that we have reached the end of the string

You mentioned alphanumeric , so in case you also want to allow digits:

(?i)^[a-z0-9]+(?:[ -]?[a-z0-9]+)*$