Conditions within loops: If or Continue?

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1

I thought of a hypothetical performance question regarding conditions within loops that would apply to most languages. Suppose you have a simple loop (I’ll use JavaScript for the example since it’s a very common language):

var favoriteJuices = new Array();
favoriteJuices["Mike"] = "Apple";
favoriteJuices["Fred"] = "Orange";
favoriteJuices["James"] = "Orange";
favoriteJuices["Samantha"] = "Grapefruit";
favoriteJuices["Jane"] = "Apple";
favoriteJuices["Elizabeth"] = "Apple";
for(var i in favoriteJuices){
	document.writeln(i+" likes "+favoriteJuices[i]);
}

Now, suppose you didn’t want to display anyone who likes apple juice. Would it be more efficient to write:

for(var i in favoriteJuices){
	if(i!="Apple"){
		document.writeln(i+" likes "+favoriteJuices[i]);
	}
}

or:

for(var i in favoriteJuices){
	if(i=="Apple") continue;
	document.writeln(i+" likes "+favoriteJuices[i]);
}

?

If there is even much of a difference, to what magnitude would performance be affected?

2

… scratch my response, I re-read it and I goofed …

3

I would say first version is more efficient, as in the second one you use additional language keyword “continue” (which will use additional CPU cycle).

An excellent book on similar topic: http://netlib.bell-labs.com/cm/cs/pearls/