Regex for ONE-or-more letters/digits And ZERO-or-more spaces

Question

I want to allow 0 or more white spaces in my string and one or more A-Z or a-z or 0-9 in my string.

Regex allowing a space character in Java

suggests [0-9A-Za-z ]+.

I doubt that, this regex matches patterns having zero or more white spaces.

What to do to allow 0 or more whitespaces anywhere in the string and one or more characters anywhere in the string.

Will this work? ([0-9A-Za-z]+)([ ]*)

Answer 1

I believe you can do something like this:

([ ]*+[0-9A-Za-z]++[ ]*+)+

This is 0 or more spaces, followed by at least 1 alphanum char, followed by 0 or more spaces

^^ that whole thing at least once.

Using Pshemo's idea of possessive quantifiers to speed up the regex.

Answer 2

The most simple answer

* means zero or more equivalent to {0,}

+ means one or more equivalent to {1,}

so look at this

[A-Z]+ means at least one Capital Letter, can be written as [A-Z]{1,}

[!@#$%&]. means you can have these Special Characters zero or more times can be written as [!@#$%&]{0,}

sorry but

the purpose of this answer to be as Simple as possible

Answer 3

You can try also this :

  ^[0-9A-Za-z ]*[0-9A-Za-z]+[ ]*$

Answer 4

Use lookahead:

^(?=.*\s*)(?=.*[a-zA-Z0-9]+)[a-zA-Z0-9 ]+$