Javascrip iterating over a for loop - logic

user_13255805 0
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Folks, I am extracting data from my collection into an array like so

obj = [{
  "PlayerName": "Satyajit Sahay",
  "Points": 83.83,
  "Rank": 1
},
{
  "PlayerName": "Chirag Galundia",
  "Points": 75.69,
  "Rank": 2
},
{
  "PlayerName": "Kashyap Kapoor",
  "Points": 70.91,
  "Rank": 3
}]

Around 190 such records. My effort is to iterate the array in a for loop. Then identify if the points are the same. If same I am assigning the same rank or else I am assigning a rank +1. Here is the code written so far

var ranking = 1
for (i = 0; i < obj[0].length; i++) {
  if (i > 0 && obj[0][i].Points < obj[0][i - 1].Points) {
    ranking++
    obj[0][i].Rank = ranking;
  } else if (i > 0 && obj[0][i].Points === obj[0][i - 1].Points) {
    obj[0][i].Rank = ranking;
    ranking++
  }
}

This works fine if 2 consecutive players have the same points. The minute the third player has the same rank it behaves weirdly. Can someone help?

javascript
1 Answers

Let's assume your array is sorted by points.

What you can do as algorithm is

  1. start with second record (i=1), with ranking = 1, step=1
  2. if score is less than previous record increase ranking by step and reset step, else increase step
  3. assign ranking
  4. go back to 2 until we have reach the end of the array

aka

let ranking=1;
let step=1
for(i=1; i<obj.length; i++){
   if(obj[i].points < obj[i-1].points){
        ranking += step;
        step = 1;
   } else {
        step++;
   }
   obj[i].ranking = ranking;
}

Some extras :

don't use var use let or const

don't forget you can start the loop further than 0, if everything has a i>0 it means we don't need the first iteration.

take a look at a array funciton (forEach() sort() find(), ...) they could come handy

don't use upercase letter to name your variables

user_47466390
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