Regular expression that allows spaces in a string, but not only blank spaces

Question

I need to write a regular expression for form validation that allows spaces within a string, but doesn\'t allow only white space.

For example - \'Chicago Heigh

Answer 1

It's very simple: .*\S.*

This requires one non-space character, at any place. The regular expression syntax is for Perl 5 compatible regular expressions, if you have another language, the syntax may differ a bit.

Answer 2

Try this regular expression:

^[^\s]+(\s.*)?$

It means one or more characters that are not space, then, optionally, a space followed by anything.

Answer 3

You could use simple:

^(?=.*\S).+$

if your regex engine supports positive lookaheads. This expression requires at least one non-space character.

See it on rubular.

Answer 4

Just use \s* to avoid one or more blank spaces in the regular expression between two words.

For example, "Mozilla/ 4.75" and "Mozilla/4.75" both can be matched by the following regular expression:

[A-Z][a-z]*/\s*[0-9]\.[0-9]{1,2}

Adding \s* matches on zero, one or more blank spaces between two words.

Answer 5

If we wanted to apply validations only with allowed character set then I tried with USERNAME_REGEX = /^(?:\s*[.\-_]*[a-zA-Z0-9]{1,}[.\-_]*\s*)$/;

• A string can contain any number of spaces at the beginning or ending or in between but will contain at least one alphanumeric character.
• Optional ., _ , - characters are also allowed but string must have one alphanumeric character.

Answer 6

The following will answer your question as written, but see my additional note afterward:

^(?!\s*$)[-a-zA-Z0-9_:,.' ']{1,100}$

Explanation: The (?!\s*$) is a negative lookahead. It means: "The following characters cannot match the subpattern \s*$." When you take the subpattern into account, it means: "The following characters can neither be an empty string, nor a string of whitespace all the way to the end. Therefore, there must be at least one non-whitespace character after this point in the string." Once you have that rule out of the way, you're free to allow spaces in your character class.

Extra note: I don't think your ' ' is doing what you intend. It looks like you were trying to represent a space character, but regex interprets ' as a literal apostrophe. Inside a character class, ' ' would mean "match any character that is either ', a space character, or '" (notice that the second ' character is redundant). I suspect what you want is more like this:

^(?!\s*$)[-a-zA-Z0-9_:,.\s]{1,100}$