Regular Expression - Match any character except +, empty string should also be matched

Question

I am having a bit of trouble with one part of a regular expression that will be used in JavaScript. I need a way to match any character other than the + character, an empty string should also match.

[^+] is almost what I want except it does not match an empty string. I have tried [^+]* thinking: "any character other than +, zero or more times", but this matches everything including +.

Answer 1

Add a {0,1} to it so that it will only match zero or one times, no more no less:

[^+]{0,1} 

Or, as FailedDev pointed out, ? works too:

[^+]? 

As expected, testing with Chrome's JavaScript console shows no match for "+" but does match other characters:

x = "+" y = "A"  x.match(/[^+]{0,1}/) [""]  y.match(/[^+]{0,1}/) ["A"]  x.match(/[^+]?/) [""]  y.match(/[^+]?/) ["A"] 

Answer 2

• [^+] means "match any single character that is not a +"
• [^+]* means "match any number of characters that are not a +" - which almost seems like what I think you want, except that it will match zero characters if the first character (or even all of the characters) are +.

use anchors to make sure that the expression validates the ENTIRE STRING:

^[^+]*$ 

means:

^       # assert at the beginning of the string [^+]*   # any character that is not '+', zero or more times $       # assert at the end of the string