Checking index like pattern with Regular Expression

I try to check a index string (e.g. $string = "[index]") with a regular expression. This index must be checked against the illegal characters [ and ] inside the index name. So for example [in[dex] must fail.

My first try:

/^\[[^\[\]]*\]$/

So the the string must start and end with [ and ]. With a negated character class I now try to make inline square brackets illegal but this doesn't work propably.

Any ideas?

Thanks in advanced,

Johnny

Edit: I'm very confused. I rerun the tests I wrote for this and it works fine now. Think I have missed something when working in the history of my editor. Thanks for h开发者_StackOverflowelp to everyone.

This /^\[[^[\]]+\]$/ worked for me.

/^\[[^[\]]+\]$/.test("[index]") // true
/^\[[^[\]]+\]$/.test("[in[dex]") // false
/^\[[^[\]]+\]$/.test("[in]dex]") // false

1. /^\[ begins with a bracket
2. [^ open "not" syntax
3. [\] exclusion characters
4. ]+ close not and say we only want 1+ things which pass the not syntax (change to asterisk to match [])
5. \]$/ Expression will end with the closing bracket.

/^\[[^][]+\]$/

Is that what you're looking for?

• Match a [ character
• Match a single character NOT present in the list "][" Between 1 and unlimited times, as many times as possible, giving back as needed (greedy)
• Match a ] character

The only reason I can see right now that your correct regex wouldn't work is if you didn't escape it properly when quoting in PHP. It should be quoted something like: "/^\\[[^[\\]]*\\]$/".

What you have should work using preg_match. If you are using ereg, then it will not work. Ereg has been deprecated as of PHP 5.3. I tried your regex out at regextester.com against the following, and it worked under preg and failed under ereg.

[index]
[in[dex]
[in[de]x]
d[index]
[inde]x]
[index]d