Tally of specified time frame

Question

Tally of specified time frame

I have a collection of dates presented as follows:

[ "2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25", ]

and I am in need of segregating consecutive identical dates into distinct ranges.

For instance, the desired output should be:

{date: "2020-08-20", period: 1-2}, {date: "2020-08-21", period: 3-3}, {date: "2020-08-25", period: 4-4},
{date: "2020-08-25", period: 5-7}

or simply put:

{date: "2020-08-20", period: 1-2},{date: "2020-08-25", period: 5-7}

If anyone could offer assistance with this task, it would be greatly appreciated. I attempted to utilize momentjs library for this purpose but encountered some challenges :(

Thank you in advance for any help provided

javascript typescript date

Answer 1

Answer №1

When analyzing the sorted date example provided, I recommend utilizing a 2 pointer solution:

Scenario 1:

var data = ["2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"];

let i = 0, j = 1;
var res = [];
while (i < data.length) {
    if (data[i] == data[j]) {
        j += 1;
        //scan rest
        while (data[i] == data[j]) {
            j += 1;
        }
        j -= 1;
        res.push({ date: data[i], period: (i + 1) + "-" + (j + 1) });
        i = j + 1;
        j = i + 1;
    } else {
        res.push({ date: data[i], period: (i + 1) + "-" + (i + 1) });
        i += 1;
        j += 1;
    }

}
console.log(res);

Scenario 2:

var data = ["2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"];

let i = 0, j = 1;
var res = [];
while (i < data.length) {
    if (data[i] == data[j]) {
        j += 1;
        while (data[i] == data[j]) {
            j += 1;
        }
        j -= 1;
        res.push({ date: data[i], period: (i + 1) + "-" + (j + 1) });
        i = j + 1;
        j = i + 1;
    } else {
        i += 1;
        j += 1;
    }

}
console.log(res);

Answer 2

When analyzing the sorted date example provided, I recommend utilizing a 2 pointer solution:

Scenario 1:

var data = ["2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"];

let i = 0, j = 1;
var res = [];
while (i < data.length) {
    if (data[i] == data[j]) {
        j += 1;
        //scan rest
        while (data[i] == data[j]) {
            j += 1;
        }
        j -= 1;
        res.push({ date: data[i], period: (i + 1) + "-" + (j + 1) });
        i = j + 1;
        j = i + 1;
    } else {
        res.push({ date: data[i], period: (i + 1) + "-" + (i + 1) });
        i += 1;
        j += 1;
    }

}
console.log(res);

Scenario 2:

var data = ["2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"];

let i = 0, j = 1;
var res = [];
while (i < data.length) {
    if (data[i] == data[j]) {
        j += 1;
        while (data[i] == data[j]) {
            j += 1;
        }
        j -= 1;
        res.push({ date: data[i], period: (i + 1) + "-" + (j + 1) });
        i = j + 1;
        j = i + 1;
    } else {
        i += 1;
        j += 1;
    }

}
console.log(res);

Answer 3

Answer №2

Here is a straightforward approach that identifies unique values in a list and then determines their periods by referencing the first and last occurrences of each value within the original array.

This method assumes that the initial list is sorted. If there are scenarios where multiple periods exist for the same date due to other intervening values, an alternative solution would be necessary along with potential specification updates.

const extractUniqueDates = (dates) =>
  [...new Set(dates)] // retrieve an array of distinct dates
    .map(date => ({   // transform each into a {date, period} object
      date, 
      period: `${dates.indexOf(date) + 1}-${dates.lastIndexOf(date) + 1}`
    }))
      
const inputDates = [ "2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"]
  
console.log(extractUniqueDates(inputDates))

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

Answer 4

Here is a straightforward approach that identifies unique values in a list and then determines their periods by referencing the first and last occurrences of each value within the original array.

This method assumes that the initial list is sorted. If there are scenarios where multiple periods exist for the same date due to other intervening values, an alternative solution would be necessary along with potential specification updates.

const extractUniqueDates = (dates) =>
  [...new Set(dates)] // retrieve an array of distinct dates
    .map(date => ({   // transform each into a {date, period} object
      date, 
      period: `${dates.indexOf(date) + 1}-${dates.lastIndexOf(date) + 1}`
    }))
      
const inputDates = [ "2020-08-20", "2020-08-20", "2020-08-21", "2020-08-24", "2020-08-25", "2020-08-25", "2020-08-25"]
  
console.log(extractUniqueDates(inputDates))

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

Tally of specified time frame

Answer №1

Answer №2

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