Why does person[prop] access the key? It appears like that would access the property.

Question

I read through the questions, and Julie Ogden's question is similar to mine, but I don't think her intended question was ever really answered.
I understand how the 'for in' loop works and functions, it just seems that the way the value of a property is accessed doesn't make sense. The below code will log each property's key belonging to an object named 'person'.
javascript
for (prop in person) {
  console.log(person[prop]);
}

but since the variable 'prop' refers to the property (not the value) being iterated, I don't understand why person[prop] would not just access the property. I understand that person[prop] accesses the key, it just seems to me like it would access the property instead.
To wrap it up, it seems to me like both of the loops below would log the properties of an object named 'person', but in fact the first loop logs the properties, and the second loop logs the values. 
```javascript
for (prop in person) {
  console.log(prop);
}
for (prop in person) {
  console.log(person[prop]);
}
```

Jennifer Nordell · Accepted Answer

Hi there!  When I was trying to wrap my head around this the first time, it was explained to me that you can sort of think of this like an array.  I'm fairly sure you're familiar with arrays at this point.  An array is an object in JavaScript with predefined keys going from 0 and counting upwards.  So to get the value in an array you need to point at that spot in the array by telling it the key.
This is the same concept with your Person object.  But the big difference here is that you determine what the keys are named.  I made a simple JavaScript snippet that you can run in the console to see how it works in an array.
```javascript
var myArr = ["Hi", "there", "Wesley"];
for (key in myArr) {
  console.log(key);
}
for (key in myArr) {
  console.log(myArr[key]);
}
```
You'll see that the first for loop logs the numbers 0 through 2 because those are what the keys are actually named.  And the second logs the values at those keys.  Hope this helps! :sparkles:

Erik Nuber · Answer

One of the big things that he tries to push in the video is that the word prop could be anything. So keep that in mind

for (var iCanBeAnything in person) {
    console.log(iCanBeAnything)
}

this would log out just the keys and it doesn't matter what the variable is.

for (var iCanBeAnything in person) {
    console.log(person[iCanBeAnything])
}

this is saying that now you need the value for each key within person.

Welcome to the Treehouse Community

Looking to learn something new?

Wesley Goldsborough

Wesley Goldsborough

Why does person[prop] access the key? It appears like that would access the property.

2 Answers

Jennifer Nordell

Jennifer Nordell

Wesley Goldsborough

Wesley Goldsborough

Jennifer Nordell

Jennifer Nordell

Hanzo Akimaru

Hanzo Akimaru

Erik Nuber

Erik Nuber