AS3 Replace section of string with a dash using RegExp - regex

Question

I would like to be able to replace a section of a string with a dash. The section being replaced will be variable.
var str:String = "permanentContainer-temporaryContainer-"
var test:String = "temp";
var pattern:RegExp = /-[(+test+)]+-/i;
trace( str.replace(pattern,"-"));
I would like the result to trace:
permanentContainer--oraryContainer-

Answer 1

var str:String = "permanentContainer-temporaryContainer-"
var test:String ="temp";
var regex:RegExp = new RegExp(test,"ig");
trace(str.replace(regex,"-"));

Answer 2

If the variable test String you are replacing doesn't use special regex matching, then simple string functions would probably be more efficient (toLowerCase achieves case insensitive match, equivalent to regex "i" option):
var str:String = "permanentContainer-temporaryContainer-";
var test:String = "temp";
var idx:int = str.toLowerCase().indexOf(test.toLowerCase());
str = str.substr(0, idx)+'-'+str.substr(idx+test.length);
trace(str);
If you want to replace all instances of the test string (equivalent to regex "g" option):
var str:String = "permanentContainer-temporaryContainer-";
var test:String = "temp";
var idx:int = str.toLowerCase().indexOf(test.toLowerCase());
while (idx>=0) {
str = str.substr(0, idx)+'-'+str.substr(idx+test.length);
trace(str);
idx = str.toLowerCase().indexOf(test.toLowerCase());
}
I tested the performance of substr vs the RegEx, and it's very close, but it turns out that the RegEx is faster (on my platform) when you start adding options like case insensitivity and global replace (via the power of native implementations), though the string approach can be optimized (i.e. calling toLowerCase only once pre-loop, or substr search starting from the last matched idx.)