group items into ranges based on property of objects

Question

group items into ranges based on property of objects

I've been grappling with this issue for far too long. Can anyone provide guidance on how to tackle the following scenario using JavaScript? The dataset consists of objects representing a date and a specific length. I need to transform this list into an object resembling a range, indicating the start and end days for each length.

If there is a missing day in the sequence, it should result in an additional range object. For example, if day 33 is removed from the sample data, it would create an extra range object (one from day 31 to 32, another from 34 to 35).

    const data = [
      { day: 31, length: 10 },
      { day: 32, length: 10 },
      { day: 33, length: 10 },
      { day: 34, length: 10 },
      { day: 35, length: 10 },
      
      { day: 68, length: 15 },
      { day: 69, length: 15 },
      { day: 70, length: 15 },
      { day: 71, length: 15 },
      
      { day: 80, length: 10 },
      { day: 81, length: 10 },
      
      { day: 98, length: 12 },
      { day: 99, length: 12 },
      { day: 100, length: 30 },
    ];


    const convertToWindows = (data) => {
      return ...;
    };

    const windows = [
      {
        start: 31,
        end: 35,
        length: 10,
      },
      {
        start: 68,
        end: 71,
        length: 15,
      },
      {
        start: 80,
        end: 81,
        length: 10,
      },
      {
        start: 98,
        end: 99,
        length: 12,
      },
      {
        start: 100,
        end: 100,
        length: 30,
      },
    ];

javascript typescript lodash data-conversion converters

Answer 1

Answer №1

Consider trying out the following approach:

const info = [
      { num: 15, value: "hello" },
      { num: 16, value: "world" },
      { num: 17, value: "foo" },
      { num: 18, value: "bar" },
      { num: 19, value: "test" },
      
      { num: 31, value: "one" },
      { num: 32, value: "two" },
      { num: 33, value: "three" },
      { num: 34, value: "four" },
      
      { num: 51, value: "apple" },
      { num: 52, value: "banana" },
      
      { num: 75, value: "alpha" },
      { num: 76, value: "beta" },
      { num: 77, value: "gamma" },
    ];

    const rearrangeData = (info) => {
      let output = [];
      info.forEach(item => {
        let len = output.length;
        if (len === 0 || output[len-1].val !== item.value) {
          output.push({start: item.num, end: item.num, val: item.value});
        } else output[len-1].end += 1;
      });
      return output;
    };

    console.log(rearrangeData(info));

Answer 2

Consider trying out the following approach:

const info = [
      { num: 15, value: "hello" },
      { num: 16, value: "world" },
      { num: 17, value: "foo" },
      { num: 18, value: "bar" },
      { num: 19, value: "test" },
      
      { num: 31, value: "one" },
      { num: 32, value: "two" },
      { num: 33, value: "three" },
      { num: 34, value: "four" },
      
      { num: 51, value: "apple" },
      { num: 52, value: "banana" },
      
      { num: 75, value: "alpha" },
      { num: 76, value: "beta" },
      { num: 77, value: "gamma" },
    ];

    const rearrangeData = (info) => {
      let output = [];
      info.forEach(item => {
        let len = output.length;
        if (len === 0 || output[len-1].val !== item.value) {
          output.push({start: item.num, end: item.num, val: item.value});
        } else output[len-1].end += 1;
      });
      return output;
    };

    console.log(rearrangeData(info));

Answer 3

Answer №2

If you're looking for a solution to your issue, consider utilizing a basic for loop.

const information = [
  { time: 31, length: 10 },
  { time: 32, length: 10 },
  { time: 33, length: 10 },
  { time: 34, length: 10 },
  { time: 35, length: 10 },

  { time: 68, length: 15 },
  { time: 69, length: 15 },
  { time: 70, length: 15 },
  { time: 71, length: 15 },

  { time: 80, length: 10 },
  { time: 81, length: 10 },

  { time: 98, length: 12 },
  { time: 99, length: 12 },
  { time: 100, length: 30 },
];
const toWindows = (arr) => {
  const result = [];
  let startingPoint = arr[0].time;
  let endingPoint = arr[0].time;
  let duration = arr[0].length;
  for (let i = 1; i < arr.length; i += 1) {
    if (
      arr[i].time - arr[i - 1].time === 1 &&
      arr[i].length === arr[i - 1].length
    ) {
      endingPoint = arr[i].time;
      duration = arr[i].length;
    } else {
      result.push({
        start: startingPoint,
        end: endingPoint,
        length: duration,
      });
      startingPoint = arr[i].time;
      endingPoint = arr[i].time;
      duration = arr[i].length;
    }
  }
  result.push({
    start: startingPoint,
    end: endingPoint,
    length: duration,
  });
  return result;
};

console.log(toWindows(information));

Answer 4

If you're looking for a solution to your issue, consider utilizing a basic for loop.

const information = [
  { time: 31, length: 10 },
  { time: 32, length: 10 },
  { time: 33, length: 10 },
  { time: 34, length: 10 },
  { time: 35, length: 10 },

  { time: 68, length: 15 },
  { time: 69, length: 15 },
  { time: 70, length: 15 },
  { time: 71, length: 15 },

  { time: 80, length: 10 },
  { time: 81, length: 10 },

  { time: 98, length: 12 },
  { time: 99, length: 12 },
  { time: 100, length: 30 },
];
const toWindows = (arr) => {
  const result = [];
  let startingPoint = arr[0].time;
  let endingPoint = arr[0].time;
  let duration = arr[0].length;
  for (let i = 1; i < arr.length; i += 1) {
    if (
      arr[i].time - arr[i - 1].time === 1 &&
      arr[i].length === arr[i - 1].length
    ) {
      endingPoint = arr[i].time;
      duration = arr[i].length;
    } else {
      result.push({
        start: startingPoint,
        end: endingPoint,
        length: duration,
      });
      startingPoint = arr[i].time;
      endingPoint = arr[i].time;
      duration = arr[i].length;
    }
  }
  result.push({
    start: startingPoint,
    end: endingPoint,
    length: duration,
  });
  return result;
};

console.log(toWindows(information));

Answer 5

Answer №3

Here is a helpful technique:
Utilize the power of Optional chaining using ?. within an Array.reduceRight() function

const data = 
  [ { day:  31, length: 10 }, { day:  32, length: 10 }, { day:  33, length: 10 }, { day:  34, length: 10 }, { day:  35, length: 10 } 
  , { day:  68, length: 15 }, { day:  69, length: 15 }, { day:  70, length: 15 }, { day:  71, length: 15 } 
  , { day:  80, length: 10 }, { day:  81, length: 10 } 
  , { day:  98, length: 12 }, { day:  99, length: 12 } 
  , { day: 100, length: 30 } 
  ]

const convertToWindows = arr => 
  arr.reduceRight((acc,{day, length}) =>
    {
    if (acc[0]?.start===(day+1) 
     && acc[0]?.length===length)
      {
      acc[0].start = day
      }
    else
      {
      acc.unshift({start:day, end:day, length})
      }
    return acc
    }
  ,[])
  ;
console.log( convertToWindows(data) )

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

Answer 6

Here is a helpful technique:
Utilize the power of Optional chaining using ?. within an Array.reduceRight() function

const data = 
  [ { day:  31, length: 10 }, { day:  32, length: 10 }, { day:  33, length: 10 }, { day:  34, length: 10 }, { day:  35, length: 10 } 
  , { day:  68, length: 15 }, { day:  69, length: 15 }, { day:  70, length: 15 }, { day:  71, length: 15 } 
  , { day:  80, length: 10 }, { day:  81, length: 10 } 
  , { day:  98, length: 12 }, { day:  99, length: 12 } 
  , { day: 100, length: 30 } 
  ]

const convertToWindows = arr => 
  arr.reduceRight((acc,{day, length}) =>
    {
    if (acc[0]?.start===(day+1) 
     && acc[0]?.length===length)
      {
      acc[0].start = day
      }
    else
      {
      acc.unshift({start:day, end:day, length})
      }
    return acc
    }
  ,[])
  ;
console.log( convertToWindows(data) )

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

group items into ranges based on property of objects

Answer №1

Answer №2

Answer №3

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