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Ann Tai
805 PointsJavascript - Loop - For vs While
Hi there,
I have understand more clearly the concept of "for." But how to understand what's within this ( ; ; )? Because from the Quiz, I don't know how to interpret the asked question (var i=0; i<10; i=i+1) but can only guess its closest format based on the video from Jim.
Thanks!
1 Answer
Samuel Webb
25,370 PointsHey Ann,
The for loop looks quite complicated, but it's actually pretty simple. The semicolons separate it into 3 parts(setting the variable, setting the condition, and updating the variable). I'll read it to you like an english statement.
(var i=0; i<10; i=i+1) -- Create a variable called i and set it to a value of 0; as long as the variable i is less than 10, run this loop; each time the loop is run, add 1 to variable i.
Basically, this is a loop that will run the code that is in the following block 10 times. For example:
for (var i=0; i<10; i=i+1) {
console.log(i);
}
The previous code is a for loop that executes the contained block of code 10 times. It will log out the numbers 0-9 to the console.
Ann Tai
805 PointsThanks Samuel and Henrik! : )
Samuel Webb
25,370 PointsGlad to help.
Henrik Holmlund
6,113 PointsHenrik Holmlund
6,113 PointsThe for-loop executes your code within the curly braces as long as what's inside the () is true. So for your example:
for(var i = 0; i < 10; i = i+1){ //some code here }
The first thing that happens is that the variable i is set to 0; the second thing (i <10) is that the for-loop will continue to do something (iterate) as long as i is less than 10. The loop then performs the code between the {}, and after that it adds 1 to the variable i (i=i+1). So now i has the value of 1 which is still less than 10, so the code between the {} will execute once more. And so again it adds 1 to i, which makes i 2. This will go on for as long as i is less than 10, if that is no longer true the for loop exits and your for-loop is done doing whatever it was supposed to do...
Hope that's clear enough, I have to run to a dentist appointment so this was written in haste, but I'll try to clarify if need be..