jQuery grep with two arrays?

Question

Is it my syntax, or is what I'm trying to do just completely the wrong way of going about this?

I have two arrays that are populated by whatever attributes the user selects. Then I'm trying to use $.grep() on a json file to select pillows that match their search. So in the example below, I'm trying to find all pillows with a "down" fill and a "low" price.

var activevars = ['fill','price']; 
var activeattributes = ['down','low']; 
pillowSelection = $.grep(data.pillow, function (a) { 
return $.inArray(a[activevars], activeattributes) > -1;
});

I'm a tenacious Googler, but this has me stumped. Thanks so much in advance for any clues.

Your question is not clear enough. How does the data.pillow data structure look like? — edwin
– edwin, Commented May 26, 2011 at 20:45
The a in the grep callback function is an array element, not an array, so you can't call a[activevars]. Also, you have to both check the key and value. Maybe you don't only have price "low", but also height "low". — edwin
– edwin, Commented May 26, 2011 at 20:48

luqui · Accepted Answer · 2011-05-26 21:16:04Z

2

If I understand correctly, activevars and activeattributes are parallel arrays, that is activevars[0] goes with activeattributes[0] and activevars[1] goes with activeattributes[1], etc.

So you could do something like this:

pillowSelection = $.grep(data.pillow, function(a) {
    for (var i = 0; i < activevars.length; i++) {
        if (a[activevars[i]] !== activeattributes[i]) {
            return false;
        }
    }
    return true;
});

If you want a more functional style, you should use an object representing the active attributes/vars (or just convert from parallel arrays); eg.

var filter = { fill: 'down', price: 'low' };

and then check whether it is a sub dictionary of each pillow:

pillowSelection = $.grep(data.pillow, function(a) {
    return sub_dictionary(filter, a);
});

edited May 26, 2011 at 21:16

answered May 26, 2011 at 20:55

luqui

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Comments

Eli · Accepted Answer · 2011-05-26 20:57:51Z

1

There seems to be something missing from your question, but I'll try to answer it like so:

If you have an array of pillow objects:

var pillows = [
    { fill: 'down', price: 'low' },
    { fill: 'cheese', price: 'middle' },
    { fill: 'water', price: 'high' },
    { fill: 'air', price: 'omg-too-much' }
];

To get a new array of pillows matching your criteria, form your query this way and it will be much easier:

var query = { fill: 'down', price: 'low' };

var matches = pillows.filter(function (pillow) {
    return pillow.fill === query.fill && pillow.price === query.price;
});

answered May 26, 2011 at 20:57

Eli

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Comments

mVChr · Accepted Answer · 2011-05-26 20:55:32Z

0

This should work for you:

var activevars = ['fill', 'price'];
var activeattributes = ['down', 'low'];
var pillowSelection = $.grep(data.pillow, function(a) {
    var ret = false;
    for (var i = 0, il = activevars.length; i < il; i++) {
        if ($.inArray(a[activevars[i]], activeattributes) > -1) {
            ret = true;
        }
    }
    return ret;
});

answered May 26, 2011 at 20:55

mVChr

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user3423593 · Accepted Answer · 2019-09-06 08:50:43Z

0

This was the way i solved my problem:

var array1 = [1,2,3,4,5],
    array2 = [5,4,3,2,1,6];

function compareArrays(arr1, arr2) {
    return $(arr1).not(arr2).length == 0
};

Then run this in a for each loop:

var hasValues = compareArrays(array1, array2) ? 'true' : 'false');

if(hasValues == true){
   // show content
}else{
   // Hide content
}

answered Sep 6, 2019 at 8:50

user3423593

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