如何在Javascript中创建数组对象

Question

I want to create the object of list that looks like this:

myObj = {"foo":[1,2,3,4], 
         "bar":[3,5,7,8]}

I tried this but failed

var myObj = new Object();
myObj["foo"].push(1)
myObj["foo"].push(2)
#...etc

What's the right way to do it?

Answer 1

You need to create the array first

myObj["foo"] = []

then call your push method

Answer 2

It depends, are you trying to reassign the myObj attribute foo with a completely new array ? Or are you trying to append to the already existing array ?

In the former case:

myObj.foo = [1,5,6,4] // new array

And in the latter:

myObj.foo.concat(/*new numbers*/)

Answer 3

The {} notation is commonly used.

var myObj = {};
myObj.foo = [];
myObj.bar = [];

Later you can manipulate the arrays.

myObj.bar.push('elem1');
myObj.bar.pop();
// ...

Answer 4

First you should declare the properties of the object as array in order not to get some unpleasent situations.So you can use new Object to create an object like this.

var myObj=new Object;

and define properties as empty arrays

myobj.prop1=[];
myObj.prop2=[];

then you can push whatever you want into prop1 or prop2 by simply reaching them inside the object as

myObj.prop1.push(someData)

OR

You can use a better way to declare this object like below

var myObj={
  prop1:[],
  prop2:[]
}

And again you can push whatever you like into them as i told above as myObj.prop1.push(data)

Answer 5

Try first declare your object, so your second line goes first

var myObj = new Object();

then you fill your object with data

myObj = {"foo":[1,2,3,4],"bar":[3,5,7,8]}

then the rest of your code should work fine

myObj["foo"].push(1) myObj["foo"].push(2)

result [ 1, 2, 3, 4, 1, 2 ]