Regex to match all " - " deliminators in filename except first and last? - regex

Question

I've been trying to write a regex to match all the " - " deliminators in a filename except the first and last, so I can combine all the data in the middle into one group, for example a filename like:
Ann M Martin - Baby sitters Club - Baby sitters Little Sister - Super Special 04 - Karen, Hannie and Nancy - The Three Musketeers.doc
Has to become:
Ann M Martin - Baby sitters Club- Baby sitters Little Sister- Super Special 04- Karen, Hannie and Nancy - The Three Musketeers.doc
So basically I'm trying to replace " - " with "- " but not the first or last instance. The Filenames can have 1 to 6 " - " deliminators, but should only affect the ones with 3, 4, 5 or 6 " - " deliminators.
It's for use in File Renamer. flavor is JavaScript. Thanks.

Answer 1

Can you not use a regex? If so:
var s = "Ann M Martin - Baby sitters Club - Baby sitters Little Sister - Super Special 04 - Karen, Hannie and Nancy - The Three Musketeers.doc";
var p = s.split(' - ');
var r = ''; // result output
var i = 0;
p.forEach(function(e){
switch(i) {
case 0: r += e; break;
case 1: case p.length - 1: r += ' - ' + e; break;
default: r += '- ' + e;
}
i++;
});
console.log(r);
http://jsfiddle.net/c7zcp8z6/1/
s=Ann M Martin - Baby sitters Club - Baby sitters Little Sister - Super Special 04 - Karen, Hannie and Nancy - The Three Musketeers.doc
r=Ann M Martin - Baby sitters Club- Baby sitters Little Sister- Super Special 04- Karen, Hannie and Nancy - The Three Musketeers.doc
This is assuming that the separator is always - (1 space, 1 dash, 1 space). If not, you need to split on - only, then trim each tokens before reconstructing.

Answer 2

Two options:
1 - You'll need to do some processing of your own by iterating through the matches using
( - )
and building a new string (see this post about getting match indices).
You'll have to check that the match count is greater than 2 and skip the first and last matches.
2 - Use
.+ - ((?:.+ - )+).+ - .+
to get the part of the string to be modified and then do a replace on the the dashes, then build your string (again using the indices from the above regex).

Answer 3

Thanks for the suggestions.
I got it to work this way
It replaces the first and last " - " with " ! ", so I can then do a simple Find and Replace of all remaining " - " with "- ", then change all the " ! " back to " - "