Finding maximum and minimum Inside array of objects

Question

I have array, lets call it fruit_shop, which contains a bunch of fruits. The fruits are objects with 3 params, name, unit_price, stock; which stands for the name of the fruit, stock in the shop and current price per unit. I need to find out which fruit has the maximum/minimum stock and which has the maximum value[unit_price*stock].

fruit_shop = [
  { name: "Apple",unit_price: 100, stock:5 },
  { name: "Mango",unit_price: 120, stock:4 },
  { name: "Orange",unit_price: 90, stock:6 }];

P.S. I am using javascript.

I was using underscore, so I used pluck on the whole thing and did a math.max/min.apply on the plucked arrays, and then find out which obj is the maximum by iterating through the array. — Ashok Kumar Sahoo
– Ashok Kumar Sahoo, Commented Oct 24, 2014 at 12:55

1983 · Accepted Answer · 2014-10-24 13:47:45Z

1

var fruit_shop = [
    { name: "Apple", unit_price: 100, stock:5 },
    { name: "Mango", unit_price: 120, stock:4 },
    { name: "Orange", unit_price: 90, stock:6 }
];
var stock = fruit_shop.map(function(x){
    return x.stock;
});
var max = Math.max.apply(null, stock);
var maxfruit = fruit_shop.reduce(function(fruits, fruit){
    if(fruit.stock === max)
        fruits.push(fruit);
    return fruits;
}, []);

// Edit: I forgot about filter. Reduce is more general,
// but for collecting values, filter is simpler.
var maxfruit = fruit_shop.filter(function(fruit){
    return fruit.stock === max;
});

The remainder should be obvious.

And don't forget it's possible for more than one fruit to have, say, the minimum stock price.

edited Oct 24, 2014 at 13:47

answered Oct 24, 2014 at 13:16

1983

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3 Comments

Ashok Kumar Sahoo Over a year ago

I used this kind of approach by using, _.pluck to create the stock. Now reading about the reduce part.

Ashok Kumar Sahoo Over a year ago

What is the use of function(fruits, fruit) If I directly try to return fruit , while using function(fruit) it gives error, cant read property of fruit.

1983 Over a year ago

fruits is the array containing all the fruits found that have the maximum value. fruit is the fruit object at each step in the iteration. See developer.mozilla.org/en/docs/Web/JavaScript/Reference/…

Aleksandar Gajic · Accepted Answer · 2014-10-24 12:54:40Z

0

One option is to sort array by unit_price and than the first one would be the max price and the last item is lowest price

fruit_shop.sort(function (a, b) {
 return b['unit_price'] - a['unit_price'];
});

max = fruit_shop[0];
min = fruit_shop[fruit_shop.length - 1];

answered Oct 24, 2014 at 12:54

Aleksandar Gajic

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Comments

ierdna · Accepted Answer · 2014-10-24 12:56:34Z

0

var maxIdx = 0;
var i = 0;
for (var i = 0; i<fruit_shop.length;i++){
     if((fruit_shop[maxIdx].unit_price*fruit_shop[maxIdx].stock)<(fruit_shop[i].unit_price*fruit_shop[i].stock)){
        maxIdx = i;
     }
}
// now maxIdx contains index of the entry with highest unitprice*stock

solution by Alex G is valid, however sorting is at least O(n*log(n)) operation while a single loop is always O(n). Probably insignificant for small arrays, but can be very different for large ones

answered Oct 24, 2014 at 12:56

ierdna

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