[regex] Regex for not empty and not whitespace

I am trying to create a regex that will return false if the String pattern contains whitespace or is empty. So far I have this

[^\s] 

I think that will make sure the string does not contain whitespace but I am unsure of how to also check to make sure it is not empty. Any help would be appreciated.

Most regular expression engines support "counter part" escape sequences. That is, for \s (white-space) there's its counter part \S (non-white-space).

Using this, you can check, if there is at least one non-white-space character with ^\S+$.

PCRE for PHP has several of these escape sequences.

In my understanding you want to match a non-blank and non-empty string, so the top answer is doing the opposite. I suggest:

(.|\s)*\S(.|\s)*

- this matches any string containing at least one non-whitespace character (the \S in the middle). It can be preceded and followed by anything, any char or whitespace sequence (including new lines) - (.|\s)*.

You can try it with explanation on https://regex101.com/.

I ended up using something similar to the accepted answer, with minor modifications

(^$)|(\s+$)

Explanation by the Expresso

Select from 2 alternatives (^$)
    [1] A numbered captured group ^$
        Beginning of line ^
        End of line $
    [2] A numbered captured group (\s+$)
        Whitespace, one or more repetitions \s+
        End of line $

/^$|\s+/ This matches when empty or white spaces

/(?!^$)([^\s])/ This matches when its not empty or white spaces

A little late, but here's a regex I found that returns 0 matches for empty or white spaces:

/^(?!\s*$).+/

You can test this out at regex101

/^[\s]*$/ matches empty strings and strings containing whitespaces only