使用JavaScript在关联数组中查找键

Question

With this associative array, I would like to find a specfic key:

var veggie_prices = new Array();
veggie_prices["serves6"] = 20;
veggie_prices["serves8"] = 25;
veggie_prices["serves10"] = 35;

If I loop through the array, I can find the values with:

var x = veggie_prices[i].value;

but how should the key be found ?

var y = veggie_prices[i].key;

Answer 1

To directly answer your question, use a for..in loop

var veggie_prices = new Array();
veggie_prices["serves6"] = 20;
veggie_prices["serves8"] = 25;
veggie_prices["serves10"] = 35;
for (var i in veggie_prices) {
  console.log(i); // output: serves6, etc..
}

However, just to be clear, javascript does not have associative arrays. What you have is an object of type array, and you just added several properties to it, in addition to the normal (albeit empty at the moment) index and other native array properties/methods (eg .length , .pop() , etc..)

Answer 2

Why are you using an array? Can you use an object instead?

var veggie_prices = {};
veggie_prices["serves6"] = 20;
veggie_prices["serves8"] = 25;
veggie_prices["serves10"] = 35;

Object.keys(veggie_prices).forEach((key) => {
  console.log('Key is: ' + key);
  console.log('Value is: ' + veggie_prices[key]);
});