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Durdona Abdusamikovna
1,553 Pointsjust an idea is it possible to iterate over arrays in the reverse order ?
Here is my answer to my one of challenges
var temperatures = [100,90,99,80,70,65,30,10];
for (var k = 0; k < temperatures.length; k+=1){
console.log(temperatures[k]);
}
in the console I see arrays in the order how they were added and from curiosity thought is it possible to display them in the reverse order ? Thank you beforehand
3 Answers
Marcus Parsons
15,719 PointsWell, hello there, stranger! :D
It's very easy :) You just reverse some of the statements inside the for loop and make "k" count backwards:
var temperatures = [100,90,99,80,70,65,30,10];
for (var k = temperatures.length; k > -1; k -= 1){
console.log(temperatures[k]);
}
Durdona Abdusamikovna
1,553 Pointslol :) you are funny and YES now I learned how to do it with loop :) Thank you again !
Marcus Parsons
15,719 PointsHaha you're of course very welcome! :) Oh, btw, I also added you on Google+ if you don't mind.
Durdona Abdusamikovna
1,553 Pointsnot at all :)
Marcus Parsons
15,719 PointsMarcus Parsons
15,719 PointsNotice one thing, though, that the conditional statement "k > -1" couldn't have been "k > 0" because once k became 0, the for loop would be done, and so that first item in the array wouldn't display.
Durdona Abdusamikovna
1,553 PointsDurdona Abdusamikovna
1,553 PointsHuh ? That is interesting :) Cool, again learned smth new :) and it is possible
Marcus Parsons
15,719 PointsMarcus Parsons
15,719 PointsIs everything clear for you about how I did that?
Durdona Abdusamikovna
1,553 PointsDurdona Abdusamikovna
1,553 Pointswhat if we say
k >= -1would it help to display the first array ?
Durdona Abdusamikovna
1,553 PointsDurdona Abdusamikovna
1,553 Pointsis it the only way ? I remember in Java we have .reverse() method how about JavaScript ?
Marcus Parsons
15,719 PointsMarcus Parsons
15,719 PointsUnfortunately, no to the first question about "k >= -1", because "k" could then become -1 and the indices of an array start at 0 and go +1 each time. So, they're only defined from 0 to some positive integer. The syntax is
k >= -1as well; you never put the equals sign first. :PWhen the for loop makes k = 0, it will execute the console.log at k = 0, and then the for loop will subtract 1 from k and check if "-1 > -1" which is false and will break the loop. Is that a little better?
Marcus Parsons
15,719 PointsMarcus Parsons
15,719 PointsHahaha yes, I completely forgot about the "reverse()" method! :D
You can just do:
But, at least you have a better understanding of how you can use for loops! :P