Dynamically building array, appending values

Question

i have a bunch of options in this select, each with values like:

context|cow
context|test
thing|1
thing|5
thing|27
context|beans

while looping through the options, I want to build an array that checks to see if keys exist, and if they don't they make the key then append the value. then the next loop through, if the key exists, add the next value, comma separated.

the ideal output would be:

arr['context'] = 'cow,test,beans';
arr['thing'] = '1,5,27';

here's what i have so far, but this isn't a good strategy to build the values..

function sift(select) {
        vals = [];
        $.each(select.options, function() {
            var valArr = this.value.split('|');
            var key = valArr[0];
            var val = valArr[1];
            if (typeof vals[key] === 'undefined') {
                vals[key] = []; 
            }
            vals[key].push(val);
        });
        console.log(vals);
}

What are you trying to do, ultimately? My instinct is that there's a better way. — Blazemonger
– Blazemonger, Commented Mar 1, 2012 at 20:10
@mblase75 good point, I usually state this looks like an XY Problem. meta.stackexchange.com/questions/66377/what-is-the-xy-problem — Erik Philips
– Erik Philips, Commented Mar 1, 2012 at 22:48

charlietfl · Accepted Answer · 2012-03-01 20:04:24Z

1

Existing code works by changing

 vals=[];

To

 vals={};

http://jsfiddle.net/BrxuM/

answered Mar 1, 2012 at 20:04

charlietfl

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Comments

Jasper · Accepted Answer · 2012-03-01 20:10:39Z

1

function sift(select) {
    var vals = {};//notice I made an object, not an array, this is to create an associative array
    $.each(select.options, function() {
        var valArr = this.value.split('|');
        if (typeof vals[valArr[0]] === 'undefined') {
            vals[valArr[0]] = ''; 
        } else {
            vals[valArr[0]] += ',';
        }
        vals[valArr[0]] += valArr[1];
    });
}

Here is a demo: http://jsfiddle.net/jasper/xtfm2/1/

edited Mar 1, 2012 at 20:10

answered Mar 1, 2012 at 20:05

Jasper

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Comments

Erik Philips · Accepted Answer · 2012-03-01 20:26:47Z

How about an extensible, reusable, encapsulated solution:

function MyOptions()
{
  var _optionNames = [];
  var _optionValues = [];
  function _add(name, value)
  {
    var nameIndex = _optionNames.indexOf(name);
    if (nameIndex < 0)
    {
      _optionNames.push(name);
      var newValues = [];
      newValues.push(value);
      _optionValues.push(newValues); 
    }
    else
    {
      var values = _optionValues[nameIndex];
      values.push(value);
      _optionValues[nameIndex] = values;
    }
  };
  function _values(name)
  {
    var nameIndex = _optionNames.indexOf(name);
    if (nameIndex < 0)
    {
      return [];
    }
    else
    {
      return _optionValues[nameIndex];
    }
  };
  var public = 
  {
    add: _add,
    values: _values
  };

  return public;
}

usage:

var myOptions = MyOptions();
myOptions.add("context", "cow");
myOptions.add("context","test");    
myOptions.add("thing","1");    
myOptions.add("thing","5");    
myOptions.add("thing","27");    
myOptions.add("context","beans");    

console.log(myOptions.values("context").join(","));
console.log(myOptions.values("thing").join(","));

working example: http://jsfiddle.net/Zjamy/

tester · Accepted Answer · 2012-03-01 19:53:38Z

0

I guess this works, but if someone could optimize it, I'd love to see.

function updateSiftUrl(select) { var
    vals = {};
    $.each(select.options, function() {
        var valArr = this.value.split('|');
        var key = valArr[0];
        var val = valArr[1];
        if (typeof vals[key] === 'undefined') {
            vals[key] = val;    
            return;
        }
        vals[key] = vals[key] +','+ val;
    });
    console.log(vals);
}

answered Mar 1, 2012 at 19:53

tester

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Comments

Ryan · Accepted Answer · 2012-03-01 20:08:04Z

0

Would something like this work for you?

$("select#yourselect").change(function(){
    var optionArray =
        $(":selected", $(this)).map(function(){
            return $(this).val();
        }).get().join(", ");
});

If you've selected 3 options, optionArray should contain something like option1, option2, option3.

edited Mar 1, 2012 at 20:08

answered Mar 1, 2012 at 19:58

Ryan

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Comments

Alexander Corwin · Accepted Answer · 2012-03-01 19:54:01Z

-1

Well, you don't want vals[key] to be an array - you want it to be a string. so try doing

        if (typeof vals[key] === 'undefined') {
            vals[key] = '; 
        }
        vals[key] = vals[key] + ',' + val;

answered Mar 1, 2012 at 19:54

Alexander Corwin

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