Question

Why is this expression returning true for character 1 or V (and others)?
How could I rewrite it so that it would return true only when it’s blank or a character from a-z?

~((^$)||(^[a-z]$))~

Answer 1

Your problem is in the middle:

||

That means:

OR the empty string OR

And the empty string can be between any character. Or no characters. Basically, you’re saying “Match anything.”

To do an OR with a regex, only use a single pipe.

You can simplify this to:

/^[a-z]?$/