Make sure all values are used in drop downs

Question

I have 4 <select> boxes with the same values:

1
2
3
4

I wish to make sure each of these values are used in the dropdowns, with no duplicates.

I can not get my head around this. I have tried looping the select boxes and picking out the values, but I can not get it to work probably. Does anyone have a quick-n-easy solution to this?

Welcome on SO! You have forgotten to post any relevant code... — A. Wolff, Mar 12 '14 at 14:00

score 2 · Accepted Answer · answered Mar 12 '14 at 14:01

2

Get the unique value list then check the length with the original array.

var arr = [1,2,3,4];

if ($.unique($('select').map(function(){ return $(this).val(); })).length === arr.length) {
   // OK
}

answered Mar 12 '14 at 14:01

xdazz

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Lets say I added a another value "-1" (e.g. used for "Choose value"), can this still be used? – janhartmann Mar 12 '14 at 14:13
Got it to work by checking for -1 before returning the .val(). Used "return;" - is this OK? ;-) – janhartmann Mar 12 '14 at 14:39
@xdazz could you explain this a bit, it appears https://api.jquery.com/jQuery.unique/ only works for DOM elements. The result of the map of selects returns an array of numbers. Also see OP's follow up question which confirms the unique issue http://stackoverflow.com/questions/22356314/ensure-all-values-are-used – Huangism Mar 12 '14 at 16:15

Игор · Answer 2 · 2014-03-12T15:37:44.890

My solution to this problem

HTML

<select id="sselect"></select>

JavaScript

var a = [1,2,2,3,4,5];
var duplicates = a;
var result = [];
$(function() {
    for ( var i = 0; i < a.length; i++) {
       var item = a[i];
    for ( var c = 0; c < duplicates.length; c++) {
          if (jQuery.inArray(item, result) == -1) {
         result.push(item);
        }
    }
}
});

for ( var i = 0; i < result.length; i++) {
 $('#sselect').append($('<option>', { 
        value: result[i],
        text : result[i] 
    }));
}

Live example of this code

Make sure all values are used in drop downs

2 Answers2

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