Instead of console.log(me[key]) could you use console.log(key) ?

Question

I am going through the PHP development path and in javascript.

in this example:

var me = {
  first_name: "Jim",
  last_name: "Hoskins",
  "Employee Number": 1
}

me["first_name"] = "James"

console.log(me.first_name);
console.log(me["last_name"]
console.log(me["Employee Number"]);
console["log"](me);

var key = "last_name";

console.log(me[key])

Could you not change the last console.log to:

console.log(key)

and then get the same result?

Answer 1 · 2015-01-12T19:31:46Z

January 12, 2015 7:31pm

Dayne,

No, you would not get the same result if you simply passed the variable "key" into your console.log statement.

You're assigning the string value of "last_name" to the variable "key", which, by itself, is just that: a string value of "last_name". If you wrote "console.log(key)", it would print the string value held in that variable to the console, which would give you "last_name".

If you want to access the "last_name" property of the "me" object, you have to tell the console.log statement that you are accessing that key within that object specifically. Thus, you must write "console.log(me[key])" for that to print out the value paired with that key in that object.

Try this out for yourself and you'll see the results, which hopefully will help to clarify what is going on here. When you assign the string value of "last_name" to your variable "key", you are simply assigning a string value to a variable, like you would anywhere else. If that string value (of "last_name") happens to match the key name in a given object (i.e. the key "last_name" within your "me" object), and you pass the variable "key" (which holds the string "last_name") in as the key that you want to access in your object, JavaScript will translate that variable into its value (in this case, the string "last_name"), see that it matches a key in that object, and then return the value paired with that key, as if you had written "console.log(me["last_name"])" in the first place.

Erik

Answer 2 · 2015-01-12T19:29:56Z

January 12, 2015 7:29pm

No, the result is different. When you console.log(me[key]) you're looking in the me object under a specific key. When you do this, you return the value associated with the key, not the key itself (in this case "hoskins".) Logging just "key" will just return "last_name."

Answer 3 · 2015-01-12T19:38:36Z

January 12, 2015 7:38pm

I see! That does make sense.

Thanks for all the help.

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Dayne Wright

Dayne Wright

Instead of console.log(me[key]) could you use console.log(key) ?

3 Answers

Erik McClintock

Erik McClintock

Michael Mayer

Michael Mayer

Dayne Wright

Dayne Wright