将键推到数组或javascript对象？

Question

I need to create an array or js object with specific keys, which should be pushed to an empty array or js object. After that, I need to push some specific values according to that keys, something like this:

var arr = ["john":["jval1","jval2"], "matt":["mval1","mval2","mval3"]]

I know that's not the rigt notation for a js object or an array, but that's the idea.

This is basically what I'm trying to do:

var keys = ["john","matt"];             //my keys
var jvals = ["jval1","jval2"];          //my values for key john
var mvals = ["mval1","mval2","mval3"];  //my values for key matt

var arr = [];

for(var i in keys) arr.push(keys[i])  //pushing the names (I need to push this names as keys so next lines should work)

for(var i in jvals) arr["john"].push(jvals[i])  //Trying to push john values, which doesn't work because "john is not a key"
for(var i in mvals) arr["matt"].push(mvals[i])  //Same.

This doesn't work at all, so how should I do this?

Answer 1

Here is the more shorter version of the code, using forEach

 var keys = ["john","matt"]; //my keys var jvals = ["jval1","jval2"]; //my values for key john var mvals = ["mval1","mval2","mval3"]; //my values for key matt var object = {} keys.forEach(function(key, index) { object[key] = index == 0 ? jvals.slice() : mvals.slice() }); console.log(object) 

Answer 2

Is this you wanted?

Declare arr as object and add keys with empty array.and then push to your keys.

 var keys = ["john","matt"]; //my keys var jvals = ["jval1","jval2"]; //my values for key john var mvals = ["mval1","mval2","mval3"]; //my values for key matt var arr = {}; for(var i in keys) arr[keys[i]]=[]; for(var i in jvals) arr["john"].push(jvals[i]); for(var i in mvals) arr["matt"].push(mvals[i]); console.log(arr); 

Answer 3

var keys = ["john","matt"];             //my keys
var jvals = ["jval1","jval2"];          //my values for key john
var mvals = ["mval1","mval2","mval3"];  //my values for key matt

var arr = {}; // not []

for(var i in keys) arr.[keys[i]] = [];  //pushing the names (I need to push this names as keys so next lines should work)

for(var i in jvals) arr["john"].push(jvals[i])  //Trying to push john values, which doesn't work because "john is not a key"
for(var i in mvals) arr["matt"].push(mvals[i])  //Same.

Answer 4

OK, I see what you are trying to do. The first issue with your code is what you do to the arr array after pushing the keys 's values into it:

for(...) {
    arr["john"].push(jvals[i]);
}

What you are doing is pretty much saying arr.john.push(...) , but arr doesn't have a property named john that is array. What arr does have is an element at the index 0 that has the value of "john" . Ie arr pretty much looks like this arr = ["john", "matt"] .

Now what you want is to do is change arr to be an object and not an array.

This way your code will look like so:

var keys = ["john","matt"];
var jvals = ["jval1","jval2"];
var mvals = ["mval1","mval2","mval3"];

var arr = {};

arr["john"] = jvals;
arr["matt"] = mvals;

// Please don't do the above

// Doing the following (using an object literal) is much better, and what most will advice when creating objects in js.

var arr = {
    john: ["jval1","jval2"],
    matt: ["mval1","mval2","mval3"]
};