Javascript Multi-Dimensional Array Problems

Question

I can't figure away around this, I want the MD array to store the name of a book and the price. I know this is easier with two arrays but really wanted to give a MD array ago in javascript. I have tried several ways but can only get the book name or the book price to display twice. Any help would be greatly appreciated.

var bookName = new Array();

for (var i = 0; i < 3; i++) 
{
bookName[i] = new Array();

    for (var j = 0; j < 1; j++) 
    {
        bookName[i] = prompt("Please enter book name!");
        bookName[[i][j]] = prompt("Please enter book price!");
        document.write(bookName[i] + bookName[[i][j]] + "</br>");
    }
}

I'm not sure what sort of structure you're wanting. Are you wanting to make it do something like [["name", "price"], ["name2", "price2"]]"? — Peter Olson
– Peter Olson, Commented Mar 30, 2012 at 14:50

Peter Olson · Accepted Answer · 2012-03-30 14:53:50Z

5

I think you should just use an array of objects for this:

var books = [];
for(var i = 0; i < 3; i++) {
  books.push({
    name: prompt("Please enter book name!"),
    price: prompt("Please enter book price!")
  });
  document.write(books[i].name + books[i].price + "</br>");   
}

If you prefer, you can do an array of arrays instead:

var books = [];
for(var i = 0; i < 3; i++) {
  books.push([prompt("Please enter book name!"), prompt("Please enter book price!")]);
  document.write(books[i][0]+ books[i][1] + "</br>");   
}

answered Mar 30, 2012 at 14:53

Peter Olson

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1 Comment

pseudosavant Over a year ago

There are many valid solutions here, but this is probably the one I would use. Most concise and easiest to follow.

bfavaretto · Accepted Answer · 2012-03-30 14:50:23Z

4

Here is how you build a 2D array:

var bookName = new Array();
for (var i = 0; i < 3; i++) 
{
    bookName[i] = new Array();
    bookName[i][0] = prompt("Please enter book name!");
    bookName[i][1] = prompt("Please enter book price!");
    document.write(bookName[i] + bookName[i][0] + ": " + bookName[i][1] + "</br>");
}

You could also do that with objects inside the array:

var bookName = new Array();
for (var i = 0; i < 3; i++) 
{
    bookName[i] = {};
    bookName[i]["name"] = prompt("Please enter book name!");
    bookName[i]["price"] = prompt("Please enter book price!");
    document.write(bookName[i] + bookName[i].name + ": " + bookName[i].price + "</br>");
}

answered Mar 30, 2012 at 14:50

bfavaretto

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2 Comments

Peter Olson Over a year ago

And use object literals and array literals instead of repeated bookName[i][prop] assignments

bfavaretto Over a year ago

@Peter, I like your answer, I'd certainly code it in a similar way. But on this answer, I decided to keep the code structure closer to the OP code, because I thought it would be easier for him to understand.

Benubird · Accepted Answer · 2012-03-30 14:51:05Z

0

Instead of this:

bookName[i] = prompt("Please enter book name!");
bookName[[i][j]] = prompt("Please enter book price!");
document.write(bookName[i] + bookName[[i][j]] + "</br>");

Do this:

bookName[i][j][0] = prompt("Please enter book name!");
bookName[i][j][1] = prompt("Please enter book price!");
document.write(bookName[i][j][0] + bookName[i][j][1] + "</br>");

I don't think I've ever seen var[[i][j]] format before...

answered Mar 30, 2012 at 14:51

Benubird

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Comments

Churk · Accepted Answer · 2012-03-30 14:54:39Z

0

u r overwriting your bookName[i]

bookName[i] = new Array(); and bookName[i] = prompt("Please enter book name!");

try this:

var bookName = new Array();
for (var i = 0; i < 3; i++)  {
    bookName[i] = new Array();
    for (var j = 0; j < 1; j++)  {
        var name = prompt("Please enter book name!");
        var price = prompt("Please enter book price!");
        bookName[i][j] = {name:name, price:price}
        document.write(bookName[i][j].name + bookName[i][j].price + "</br>");
    }
}

edited Mar 30, 2012 at 14:54

answered Mar 30, 2012 at 14:48

Churk

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2 Comments

J. Doe Over a year ago

Can you explain what this part is doing please? bookName[i][j] = {name:name, price:price}

Churk Over a year ago

It is assign bookName[i][j] an hashmap like object with key = name and value = (variable name), and same with price key = 'price' and value = price (variable)

Esailija · Accepted Answer · 2012-03-30 14:55:27Z

0

A multidimensional array doesn't make much sense here, you probably want an array of objects.

var books = [], i = 3;

while( i-- ) {
    books.push({
        name: prompt("Please enter book name!"),
        price: prompt("Please enter book price!")
    });
}

answered Mar 30, 2012 at 14:55

Esailija

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Comments

Bergi · Accepted Answer · 2012-03-30 14:55:52Z

I'm not sure what you are doing there. Please make yourself familiar with the concept of Arrays, Objects and accessing of properties in JavaScript.

var bookName = new Array();

for (var i = 0; i < 3; i++) 
{
bookName[i] = new Array();
// the i. item of bookname holds an empty array now

    for (var j = 0; j < 1; j++) 
    {
        bookName[i] = prompt("Please enter book name!");
// you're overwriting the array just created with a string now
        bookName[[i][j]] = prompt("Please enter book price!");
// this is absolutely invalid syntax
        document.write(bookName[i] + bookName[[i][j]] + "</br>");
// as well as this
    }
}

What you wanted to do:

var bookName = new Array();
for (var i = 0; i < 3; i++) {
    bookName[i] = new Array();
    for (var j = 0; j < 1; j++) {
        // this is absolute ugly in a for loop:
        if (j==0)
            bookName[i][j] = prompt("Please enter book name!");
        else if (j==1)
            bookName[i][j] = prompt("Please enter book price!");
    }
    // direct accessing is better:
    document.write(bookName[i][0] + bookName[i][1] + "</br>");
}

but it would be much easier so:

var bookName = [];
for (var i = 0; i < 3; i++) {
    bookName[i] = {
        name: prompt("Please enter book name!"),
        price: prompt("Please enter book price!")
    };
    document.write(bookName[i].name + bookName[i].price + "</br>");
}

Hubert Boma Manilla · Accepted Answer · 2012-03-30 14:57:59Z

0

var bookName = [];

for (var i = 0; i < 3; i++)

{
  var b = bookName[i];
  b = [];
  for (var j = 0; j < 1; j++) 
  {
    bookName[i] = prompt("Please enter book name!");
    b[j] = prompt("Please enter book price!");
    document.write(bookName[i] + b[j] + "</br>");
  }
}

This should do it..

answered Mar 30, 2012 at 14:57

Hubert Boma Manilla

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