Question

sorry for my english

I am trying replace everything that is not %d, %m or %Y from a string, I have been trying but I do not get it, here is my best attempt code:

var old_string = "%l %d de %M de %Y (Semana %W)";               
string = old_string.replace(/[^(%d|%m|%Y)]/g, " ");             
alert(old_string + " <----> " + string);

Some help?
What am I doing wrong?

Answer 1

If I understand correctly, you want to the substrings %d, %m and %Y from your string. I assume you want one space between each match, and want to retain the original order of occurrence.

You can do this using String.match() and Array.join(), like so:

var old_string = "%l %d de %m de %Y (Semana %W)";
var matches = old_string.match(/%[dmY]/g);
var new_string = matches.join(" ");

alert(new_string); // "%d %m %Y"

Edit: here is a working demo: http://jsfiddle.net/PPvG/Gv3rX/1/

Edit (2): I realised the regular expression could be simplified further.