Regex code only allows a single space

Question

I have this regex (^[a-z]\s{1})+. It is supposed to match only letters that are separated by a single space but it still returns true even with this input:

"a a    a"

I want it to reject the expression if it has two consecutive spaces. Can you help me?

Please give this a read: http://stackoverflow.com/questions/22937618/reference-what-does-this-regex-mean/22944075#22944075 — Heretic Monkey, May 19 '16 at 14:35
It appears you forgot to ask a question. Questions without a clear problem statement are not useful and [off topic](/help/on-topic). — zzzzBov, May 19 '16 at 14:37
What do you want to achieve? Fail that string match? Try `/^[a-z](?:\s[a-z])*$/` — Wiktor Stribiżew, May 19 '16 at 14:38
Checking for two consecutive spaces would not require regex, `"a a a".indexOf(" ") >= 0` — Adam Konieska, May 19 '16 at 14:46

score 1 · Accepted Answer · answered May 19 '16 at 14:51

This is a regex that fixes this: ^\s*([a-z]\s|[a-z]$)+\s*$

Explanation:

It matches the string up to the end ($) so it will discard your example line
It matches the case when the string ends with a letter - [a-z]$
It ignores leading and trailing spaces: \s* at the beginning and the end

You can play with this here.

Regex code only allows a single space

1 Answers1