PHP preg_match needed to ensure only ONE space character is allowed between words

Question

basically I need a preg_match that ensures that only one space character is allowed between each word (IF there is more than one word).

My existing rule is:

Answer 1

i think to specify a number of occurences to your match you put i.e{1} {1,5} (to match only 1 or between 1 and 5 inclusive) so something like...

^[A-Za-z]+( {1})$