如何在javascript中将子对象分配给变量？

Question

I have a javascript object that looks like

var obj = {
    p1: {
        name: "name1",
        age: "age1"
    }
    p2: {
        name: "name2",
        age: "age2"
    }
}

I want to be able to access name and age iteratively, meaning something like this:

for (var p in obj) {
    if (obj.hasOwnProperty(p)) {
        func1(p.name);
        func2(p.age);
    }
}

However, p.name is shown as "undefined" in debugger, so are the other keys of p. I wonder if javascript allows users to assign sub-object to a new variable like in Python.

Answer 1

I think you're missing something there. Look:

for (var p in obj) {
    if (obj.hasOwnProperty(p)) {
        func1(obj[p].name);
        func2(obj[p].age);
    }
}

This should work.

p only exists as a property of obj so, even inside a for-in loop, you still have to access p as a property of obj (from the loop).

If you're learning javascript, this may not be obvious but there's actually two ways to access object properties: dot notation and the square brackets notation. Using your example, obj.p1.name === obj['p1']['name] .

Sometimes you need square brackets notation because you want to pass it some variable, which is what you need inside the for-in loop.

I hope this is clear. If not, you can see it working on this JSBin

Answer 2

Your nested object is strictly formatted (has name, age in all nested elements).
Also what's the reason to check that it hasOwnProperty ?
You iterate an object by keys and don't know it has iterator key ?

Why not just simply iterate the object?

 var obj = { p1: { name: "name1", age: "age1" }, p2: { name: "name2", age: "age2" } }; function func1(value) { console.log('Name:', value); } function func2(value) { console.log('Age:', value); } for(var i in obj) { if(typeof obj[i] != 'object') continue; console.log('\\nOutputing:', i); func1(obj[i].name); func2(obj[i].age); }