How and why does this function and loop work


#1

var friends = {
bill: {
firstName: "Bill",
lastName: "Gates",
number: "(206) 555-5555",
address: ["One Microsoft Way","Redmond","WA","98052"]
},
steve: {
firstName: "Steve",
lastName: "Jobs",
number: "222-222-222",
address: ["One Microsoft Way","Redmond","WA","98052"]
}
};

var list = function (anythingrandom) {
for (var morerandom in anythingrandom) {
console.log(morerandom);
}
};

list(friends);


#2

@paulcilien,

+++++ nyc object and the for-in loop explained ++++++++++++++++

T h e - B a s i c s

An object has one or more properties seperated by a comma-,
Each property consists of a property-key and it's associated VALUE

var nyc = {
       fullName: "New York City",
       mayor: "Bill de Blasio",
       population: 8000000,
       boroughs: 5
      };
nyc -object- S p e c i f i e d

The nyc object has 4 properties seperated by a comma-,
- a fullName property with property-key fullName and it's associated string value of "New York City"
- a mayor property with property-key mayor and it's associated string value of "Bill de Blasio"
- a population property with property-key population and it's associated number value 8000000
- a boroughs property with property-key boroughs and it's associated number value 5

for - in - loop - e x p l a i n e d

With the for-in-loop you have a Method
which will iterate over all properties of a given object.
At each iteration it will assign the property-key as a string
to a variable name of your choice.
Thus for (var x in nyc)
will lead to 4 iteration's
iteration-1 var x = "fullName";
iteration-2 var x = "mayor";
iteration-3 var x = "population";
iteration-4 var x = "boroughs";
As they want you to display the property-key and NOT it's associated VALUE
you would use
console.log( x );

If they wanted you to display the associated VALUE of the propery-key you would use
console.log( nyc[x] );


#3

This may be the best explanation of a lesson I've read so far for this course. Thank you, now I have an understanding of what these puzzle pieces do, instead of just where to put them.