Using Javascript to pick a random city

Question

I'm trying to make a javascript program that will pick a departure and arrival city for imaginary flights. I've tried to go about it a couple different ways, I have this so far, but its still not working...(this is just for the arrival city)

Arrive

    <p id = "arrival"></p>

    <script type = "text/javascript">
        function arriveRandom() {
        var arv  = ["Houston" , "Atlanta" , "Honolulu" , "Paris"];
        var dept = ["Atlanta" , "Salt Lake City" , "Kennedy Intl" , "Los Angeles" , "San Fransisco"];
        var randArv = randomGenerator(0, arv.length);
        var item = array[randArv]

        document.getElementById("arrival").innerHTML = "item";

        }

Where is your `randomGenerator()` function? What are the results that you get? — krillgar, Jun 06 '14 at 15:45
I believe in the last line, `"item"` should actually be `item`. — tcooc, Jun 06 '14 at 16:30

Sam Creamer · Answer 1 · 2014-06-06T17:18:56.607

2

Use Math.random();

function arriveRandom() {
    var arv  = ["Houston" , "Atlanta" , "Honolulu" , "Paris"];
    var dept = ["Atlanta" , "Salt Lake City" , "Kennedy Intl" , "Los Angeles" , "San Fransisco"];
    var randArv = arv[Math.round(Math.random()*(arv.length-1))];
    var randDept = dept[Math.round(Math.random()*(dept.length-1))];

    // now randArv and randDept have random arrivals and departures
    }

edit: thanks to Robert Contardo Wirth. He pointed out that my random number actually is not an integer. Add Math.round() as he suggested and this should work fine.

edited Jun 06 '14 at 17:18

answered Jun 06 '14 at 15:49

Sam Creamer

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1

I think it should be `(* arv.length - 1)`, as arrays are zero-indexed (?) – miraculixx Jun 06 '14 at 15:52

score 1 · Answer 2 · answered Jun 06 '14 at 15:57

1

In addition to Sam Creamer's response I think Math.round should be used to get an integer. Example:

var randArv = arv[Math.round(Math.random()*(arv.length-1))];

answered Jun 06 '14 at 15:57

Roberto Contardo Wirth

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Using Javascript to pick a random city

2 Answers2