Stuck sorting and seperating a nested array in JS

Question

so I'm trying to find any way to separate this array based on ID's.

[ [ 1, 123412341234, 2.44 ], [ 1, 123912341234, 23.44 ], [ 1, 623412341234, 82.44 ], [ 2, 123412341234, 22.44 ], [ 2, 123412381234, 2.44 ], [ 2, 723412341234, 29.44 ], [ 3, 123412341234, 24.44 ], [ 3, 123412377234, 34.44 ], [ 3, 520312341234, 54.44 ], [ 4, 123412341234, 12.44 ], [ 4, 938412341234, 19.44 ], [ 4, 603412341234, 10.44 ] ]

weather in separate array or in the same array but with an additional [] around the data with same ID

so this
[
    [[ 1, 123412341234, 2.44 ], [ 1, 123912341234, 23.44 ], [ 1, 623412341234, 82.44 ]], 
    [[ 2, 123412341234, 22.44 ], [ 2, 123412381234, 2.44 ], [ 2, 723412341234, 29.44 ]], 
    [[ 3, 123412341234, 24.44 ], [ 3, 123412377234, 34.44 ], [ 3, 520312341234, 54.44 ]], 
    [[ 4, 123412341234, 12.44 ], [ 4, 938412341234, 19.44 ], [ 4, 603412341234, 10.44 ]]
]

or this

[[ 1, 123412341234, 2.44 ], [ 1, 123912341234, 23.44 ]] 
[[ 2, 123412341234, 22.44 ], [ 2, 123412381234, 2.44 ], [ 2, 723412341234, 29.44 ]]  
[[ 3, 123412341234, 24.44 ], [ 3, 123412377234, 34.44 ], [ 3, 520312341234, 54.44 ]]     
[[ 4, 123412341234, 12.44 ], [ 4, 938412341234, 19.44 ], [ 4, 603412341234, 10.44 ]]

This is what I tried to make by myself but it's not working ( the c[i] is not working)

 for(let i = 0; i < this.z.length;i++) {
     for (let j = 0; j < this.z.length; j++) {
         if(this.z[j][0]==i){
             this.c[i].push(this.z[j]) 
         }                      
     }        
 }

First question: Why aren't you using sort() with a custom sorting function? — tadman
– tadman, Commented May 30, 2021 at 11:32
I used sort() to get the array I'm working with now... I tried tinkering with it but I can't get what I need. and "not working" means that nothing gets pushed into the "c" array. In all honesty I am fairly oblivious and miss obvious stuff (hell I spent 2 weeks in frustration before realizing I'm working with vue 3 and not vue 2) — PeopleCallMeLucifer
– PeopleCallMeLucifer, Commented May 30, 2021 at 11:36

Nina Scholz · Accepted Answer · 2021-05-30 12:06:49Z

1

You could group the array by checking the predecessor and build a new group for a changing first value of the inner array. This approach needs a sorted array.

const
    data = [[1, 123412341234, 2.44], [1, 123912341234, 23.44], [1, 623412341234, 82.44], [2, 123412341234, 22.44], [2, 123412381234, 2.44], [2, 723412341234, 29.44], [3, 123412341234, 24.44], [3, 123412377234, 34.44], [3, 520312341234, 54.44], [4, 123412341234, 12.44], [4, 938412341234, 19.44], [4, 603412341234, 10.44]],
    result = data.reduce((r, row, i, a) => {
        if (!i || a[i - 1][0] !== row[0]) r.push([]);
        r[r.length - 1].push(row);
        return r;
    }, []);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited May 30, 2021 at 12:06

answered May 30, 2021 at 11:38

Nina Scholz

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3 Comments

PeopleCallMeLucifer Over a year ago

thanks for the help, but I phrased my question in a very stupid and wrong way. The data I have is sorted. I need to separate it somehow based on the ID (the first value in the inner arrays) so I can forward that value to a chart Once again I am sorry, for the confusion

Nina Scholz Over a year ago

@PeopleCallMeLucifer, sorry please see edit.

PeopleCallMeLucifer Over a year ago

You just saved me a few days of frustration. Thank you very muh

me.nkr · Accepted Answer · 2021-05-30 12:30:15Z

1

const array = [
  [1, 123412341234, 2.44],
  [1, 123912341234, 23.44],
  [1, 623412341234, 82.44],
  [2, 123412341234, 22.44],
  [2, 123412381234, 2.44],
  [2, 723412341234, 29.44],
  [3, 123412341234, 24.44],
  [3, 123412377234, 34.44],
  [3, 520312341234, 54.44],
  [4, 123412341234, 12.44],
  [4, 938412341234, 19.44],
  [4, 603412341234, 10.44]
];
let result = [];
for (let id = 0; id < 4; id++) {
  result[id] = [];
  for (let index = 0; index < array.length; index++) {
    if (array[index][0] === id+1) {
      result[id].push(array[index]);
    }
  }
}


console.log(result) ;

answered May 30, 2021 at 12:30

me.nkr

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