How to replace question marks inside a string with the values of an array?

var s = 'Hello ?, welcome to ?';
var a = ['foo', 'bar'];
var i = 0;
alert(s.replace(/\?/g,function(){return a[i++]}));

Kind of silly to put it all on one line, but:

var str = 'Hello ?, welcome to ?',
    arr = ['foo', 'bar'],
    i = 0;


while(str.indexOf("?") >= 0) { str = str.replace("?", arr[i++]); }

You could use vsprintf. Although if you include sprintf, it's much more than one line.

vsprintf('Hello %s, welcome to %s', [foo, bar]);