Pattern Match all combinations 1

[JJ1]

Could anyone help me with this problem please:

I would like to match the letters "E", "N" and "L" in a string. All these letters must be present, but in any order.

Therefore, the following are possible:
[red]"ENL" or "ELN" or "LEN" or "ELN" or "NEL" or "NLE" etc...[/red]

I thought something like this maight work:
[red]if( $string =~ m/ELN/g ){
#Do something...
}[/red]
but it doesn't seem to.

Thanks in advance for any help.
Cheers,

James.

 

[JJ1]

I think I may have solved it like this:
[red]
if ($string =~ m/^[E|N|L][E|N|L][E|N|L]$/) {
$content = "ENL";
}
[/red]

If anyone knows any tidier way, then please let me know!

All the best,

James.

 

[MikeLacey]

I think the longer pattern, is more readable

if(/ENL|ELN|LEN|LNE|NLE|NEL/){
# it's in here somewhere!
}

Depends which way you think I suppose -- but spare a thought for thick people like me who might have to maintain your code afterwards. Mike

"Experience is the comb that Nature gives us, after we are bald."

Is that a haiku?
I never could get the hang
of writing those things.

 

[justice41]

James,

your regex will also match things like 'EEE', 'LLN', etc. which seem to fall outside your specifications.

btw, the pipe char, '|', is treated as a literal character in a character set (characters grouped together in []). it's not or'ing the letters together like you intend. What you probably meant to do was

 m/^[ENL][ENL][ENL]$/
# or
 m/^[ENL]{3}$/

but you still have the aforementioned problem of matching strings with repeated characters.

Mike's solution is probably what your are looking for (at least for three characters or less).

jaa

 

[dummy33]

This one has been driving me crazy.
Mike's solution works, but what if it was a 6 character string? Maybe a regex wouldn't be the best option.
There's a quantifier - {MIN,MAX} which means "match MIN times but no more than MAX times" which might do the trick but I can't seem to get it to work.

anyone?

 

[justice41]

I came up with a two-regex solution. It works for any number of characters as long as each character is unique in the desired set.

if ($string =~ /^[ENL]{3}$/ and $string !~ /([ENL])(?=.*\1)/) {

    print "Match!\n";

}

jaa

 

[icrf]

Wow, justice, I really like that one. Something I'd of been hard pressed to come up with. Curious, what does the ?= do for you in this case? I'm not sure I've ever used the regex assertions before. ----------------------------------------------------------------------------------
...but I'm just a C man trying to see the light

 

[justice41]

Curious, what does the ?= do for you in this case?

Um, in this case nothing. It works just as well without it.

$string !~ /([ENLZ]).*\1/

Thanks. I don't know why it stuck me first to do it that way.

jaa

 

[MikeLacey]

I like Jaa's solution I think, neat. Mike

"Experience is the comb that Nature gives us, after we are bald."

Is that a haiku?
I never could get the hang
of writing those things.