Question

Can you please provide me with a regular expression that would

• Allow only alphanumeric
• Have definitely only one hyphen in the entire string
• Hyphen or spaces not allowed at the front and back of the string
• no consecutive space or hyphens allowed.
• hypen and one space can be present near each other

Valid – “123-Abc test1″,”test- m e”,”abc slkh-hsds”
Invalid – ” abc “, ” -hsdj sdsd hjds- “

Thanks for helping me out on the same. Your help is much appreciated

Answer 1

/^([a-zA-Z0-9] ?)+-( ?[a-zA-Z0-9])+$/

See demo here.

EDIT:

If there can’t be a space on both sides of the hyphen, then there needs to be a little more:

/^([a-zA-Z0-9] ?)+-(((?<! -) )?[a-zA-Z0-9])+$/
                    ^^^^^^^^ ^

Alternatively, if negative lookbehind assertions aren’t supported (e.g. in JavaScript), then an equivalent regex:

/^([a-zA-Z0-9]( (?!- ))?)+-( ?[a-zA-Z0-9])+$/
              ^ ^^^^^^^ ^