I have the following code;
namedarray['India']='New Delhi';
namedarray['Australia']='Canberra';
namedarray['Indonasia']='Jakarta';
namedarray['Iran']='Tehrani';
namedarray['Iraq']='Bhagdad';
namedarray['Nijeria']='Abuja';
document.getElementById('question').innerHTML="Q." +namedarray['Nepal']+" is capital for which country";
In place of Nepal, I want to choose a key from the object at random. How can I do this?
Try this:
function fetch_random(obj) {
var temp_key, keys = [];
for(temp_key in obj) {
if(obj.hasOwnProperty(temp_key)) {
keys.push(temp_key);
}
}
return obj[keys[Math.floor(Math.random() * keys.length)]];
}
var random_name = fetch_random(namedarray);
document.getElementById('question').innerHTML="Q." + random_name +" is capital for which country"
obj is the object which is passed in. The way it works is it iterates through all of the properties of the object, and adds that to an array, which we then return a random element of that array of keys, which in turn we pass it to the object to fetch the actual value out.keys = [] is assigning a real array to a variable called keys, so we can then fetch a random key out of it.If you are capable of using libraries, you may find that Lo-Dash JS library has lots of very useful methods for such cases. In this case, go ahead and check sample().
(Note Lo-Dash convention is naming the library object _. Don't forget to check installation in the same page to set it up for your project.)
_.sample([1, 2, 3, 4]);
// → 2
In you case, go ahead and use:
_.sample(namedarray)
and in context:
document.getElementById('question').innerHTML="Q." +_.sample(namedarray)+" is capital for which country";
On a side note, you could use a simpler notation for populating the array.
namedarray = {
India : 'New Delhi',
Australia : 'Canberra',
Indonasia : 'Jakarta',
Iran : 'Tehrani',
Iraq : 'Bhagdad',
Nijeria : 'Abuja'
}
I would just use two arrays for the data.
var countries = ['India', 'Australia', 'Indonasia', ... ];
var capitols = ['New Delhi', 'Canberra', 'Jakarta', ...];
Then insert into your text with:
var index = Math.floor(Math.random() * capitols.length);
document.getElementById('question').innerHTML="Q." +capitols[index]+" is capital for which country";
You can then use the index variable to look up the answer later on as well.
