Regular expression that accepts alphanumeric , non consecutive dash and non consecutive white space

Question

Can anyone help me create a regular expression that accepts alphanumeric (numbers and letters only) and dashes and white spaces.

It shouldn\'t accept consecutive das

Answer 1

Try this:

^[A-Za-z0-9]+(?:[\s-][A-Za-z0-9]+)*$

When the first [A-Za-z0-9]+ runs out of letters and digits, the [\s-] inside the group tries to match a hyphen or a whitespace character. If it succeeds, the second [A-Za-z0-9]+ tries to match some more alphanumerics. And the group gets repeated as many times as necessary.