How to Use For/in Loop


#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: "(206) 535-5255",
        address: ['Apple','Redmond','WA','98062']
    }
        };
var list = function(friends){
    {
    for(var key in friends){
        console.log(friends[key]);
    }
}
};
list(friends.bill);

01.Create a function list that takes a single parameter.
02.In the body of the function, write a for/in loop.
03.In the loop, use console.log to print out the key. (For example, if you only have bill and steve as entries, list should just print out “bill” and “steve”.)
These were the Instructions Given to Me.
I am pretty much confused how to log the data on screen and moreover Im not able to understand what is to be printed

var list = function(friends){
    {
    for(var key in friends){
        console.log(friends[key]);
    }
}
};

what should be used in the place of Key(bill or steve) or Else is there a possibility to pass parameter as bill or steve instead of friends in the function
and how to log the data perfectly to the console.Thank you in Advance


#2

Maybe you find the answer in

+++ friends object explained

var friends= {
              bill: { firstName: 'Bill',
                      lastName: 'Gates',
                      number: '444-444-4444',
                      address: [ 'One Microsoft way', 'Redwood', 'WA' ]
              },
             steve: {
                      firstName: 'Steve',
                      lastName: 'Jobs',
                      number: '333-333-3333',
                      address: [ 'Two infinite loop', 'Bentown', 'DV' ] 
              }
   };

keep repeating these two lines
An object has one or more properties separated by a comma-,
Each property consists of a property-key and it’s associated value

Description of the friends object.
The friends object has 2 properties and are separated by a comma-,

there is a bill property with property-key bill and it’s associated object value
(this associated object has 4 properties, the property-keys being firstName, lastName,number and address)
there is a steve property with property-key steve and it’s associated object value
(this associated object has 4 properties, the property-keys being firstName, lastName,number and address)

access via dot-notation == only literal property-key allowed

friends.bill ==> you will get the associated value of the bill property-key, thus
you get the object with 4 properties

friends.bill.lastName ==> you will get the associated value of the lastName property-key

access via the square-bracket-notation == literal & VARIABLE

1 using the literal property-key

friends[“bill”]
friends[“bill”][“lastName”]

2 using the property-key by reference (=== via a variable )

var propertyKey1 = “bill”;
var propertyKey2 =“lastName”;
friends[propertyKey1] ==> you will get the associated value of the bill property-key, thus
you get the object with 4 properties

friends[propertyKey1][propertyKey2]
in this case you will get the string VALUE of the lastName property
of the associated object VALUE of bill

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

T h e - B a s i c s

An object has one or more properties separated 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 separated 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

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