Loops

Question

I'm having a difficult time understand the syntax of the loop. I've looked at the Loop video 3 times. An example of what I don't understand.

var friends = ["Nick, "Michael", "Amit", "Allison Grayce"];
console.log(friends);
console.log(friends.length);

var friendNumber = 1;
console.log(friends[friendNumber]);

for(var i=0; i<4; i+=1)

So variable is 0. So 0 is less than 4?? And I'm having trouble with the i+=1 concept. I understand i=i+1 meaning if I put in 0 i get 1=2, 2=3. That's easier for me to understand because of the simple math. The i<4 confuses me. The length is 0 1 2 3 so <4 is the max until it becomes false?

Answer 1 · 2014-10-21T23:51:04Z

October 21, 2014 11:51pm

for(var i=0; i<4; i+=1) Let's break this down into the components of the for loop:

var i=0; is declaring a variable and initial value to be used in the loop
i<4; this is an if statement. If i is less than 4, run the loop
i+=1 this is the code that is run after ever iteration of a for loop. After the loop goes through once, i will be equal to i + 1

So, as you know, the program will console.log(friends[i]); 4 times, 0 through 3.

i is set to 0, i is less than 4, console.log is run, i is incremented by 1, making it's value 1. i is less than 4, console.log runs, i is incremented by 1, making it's value 2 . . . and so on, until i is equal to 4, making the loop stop.

Does that make sense?

Answer 2 · 2014-10-21T23:47:53Z

October 21, 2014 11:47pm

The I+=1 is an incrementor.

Same as saying i=i+1

So at the end of the loop, I changed to 1 from 0.

Then the loop is ran again.

Every time the loop is ran, i increments by one. Until i is no longer < 4 in this case. At that point the loop stops

Answer 3 · 2014-10-21T23:58:38Z

October 21, 2014 11:58pm

Thanks guys I understand it now!!

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Loops

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