数组中的日期范围比较

Question

我正在尝试比较数组中的日期是否重叠但有问题。用户可以添加任意数量的日期，我需要检查它们以确保没有重叠。

日期数组（开始日期和结束日期之间用 (-) 组合：

dates (4) ["02/07/2018-02/07/2018", "02/05/2018-02/07/2018", "02/06/2018-02/06/2018", "02/08/2018-02/08/2018"]

我的代码：

        function CheckOverlappingDates(dates) {
        var startDate = []; 
        var endDate = [];
        var isOverlap;
        for (var i = 0; i < dates.length; i++) {
            var split = dates[i].split('-');  // just split once
            startDate.push(new Date(split[0]).toLocaleDateString());
            endDate.push(new Date(split[1]).toLocaleDateString());

            for (var x = 0; x < startDate.length; x++) {
                if (startDate[x] >= startDate[x + 1] && startDate[x + 1] <= endDate[x + 1]) {
                    isOverlap = true;
                } else {
                    isOverlap = false;
                }
            }

        }

    }

我将它们分成开始日期和结束日期，如下所示

但我的函数不比较多个日期范围。

Answer 1

您可以使用for循环来检查。

var dates = ["02/07/2018-02/07/2018", "02/05/2018-02/07/2018", "02/06/2018-02/06/2018", "02/08/2018-02/08/2018"];
var overlaps = checkOverlaps(dates);

console.log("overlaps", overlaps);

var dates1 = ["02/07/2018-02/07/2018", "02/08/2018-02/10/2018", "02/19/2018-02/20/2018", "02/21/2018-02/21/2018"];
var nonoverlaps = checkOverlaps(dates1);

console.log("nonoverlaps", nonoverlaps);

var dates2 = ["02/07/2018-02/07/2018", "02/07/2018-02/10/2018"]; /* 2nd range starts on the end of the first range */
var overlaps2 = checkOverlaps(dates2);

console.log("overlaps", overlaps2);

function checkOverlaps(dates) {
  var o = false;

  for (var key1 in dates) {
    var cDateArr = dates[key1].split("-");
    var d1 = new Date(cDateArr[0]);
    var d2 = new Date(cDateArr[1]);

    for (var key2 in dates) {

      //make sure not comparing to own self
      if (key1 != key2) {
        var cDateArrB = dates[key2].split("-");
        var dB1 = new Date(cDateArrB[0]);
        var dB2 = new Date(cDateArrB[1]);

        if (
          (d1 < dB1 && d2 > dB1) ||
          (d1 < dB2 && d2 > dB2) ||
          cDateArr[0] == cDateArrB[0] ||
          cDateArr[0] == cDateArrB[1] ||
          cDateArr[1] == cDateArrB[0] ||
          cDateArr[1] == cDateArrB[1]
        ) {
          o = true;
        }
      }
    }
  }

  return o;
}

Answer 2

比较日期字符串时，您可以将它们转换为日期对象或将它们保留为字符串并使用localeCompare。不要使用内置的日期解析器，因为它不可靠。一个 2 行函数可以将格式设置为字符串或转换为日期，字符串可能更有效但比较日期是更少的代码。

要查看范围数组是否有重叠，需要将每个范围与数组中它后面的范围进行比较。之前已经查过了，没必要再查了。

不清楚应该如何处理重叠范围，因此此函数只是 returns 一个包含 "range A overlaps range B" 的字符串数组。它还假定范围包含在内，因此 02/05/2018-02/07/2018 与 02/07/2018-02/08/2018 重叠。

例如

var dates = ["02/07/2018-02/07/2018", "02/05/2018-02/07/2018", "02/06/2018-02/06/2018", "02/08/2018-02/08/2018"];

// Assume array of ranges in format mm/dd/yyyy-mm/dd/yyyy
// Return array of overlapping ranges
function inRange(dates) {

  // Parse date string to Date
  function fn(s) {
    var b = s.split(/\D/);
    return new Date(b[2], b[0]-1, b[1]);
  }
  
  // Return true if range a overlaps range b
  // where range is string in format mm/dd/yyyy-mm/dd/yyyy
  // Overlaps if start or end of b are inside a, or
  // a is wholly inside b
  function overlaps(a, b) {
    a = a.split('-').map(fn);
    b = b.split('-').map(fn);
    return (b[0] >= a[0] && b[0] <= a[1]) || // b start in a
           (b[1] >= a[0] && b[1] <= a[1]) || // b end in a
           (b[0] <= a[0] && b[1] >= a[1]);   // b encloses a
  }
  
  // Array for overlapping ranges
  var overlappers = [];
  var max = dates.length - 1;

  dates.forEach(function(date, i) {
  
    // Don't test last as already tested
    if (i < max) {
    
      // Only test from this element to end of array
      for (var j = i+1; j <= max; j++) {
      
        // If overlaps, add to overlappers array
        if (overlaps(date, dates[j])) {
          overlappers.push(date + ' overlaps ' + dates[j]);
        }
      }
    }
  });
  return overlappers;
}

console.log(inRange(dates));

简单解析器要求日期有效。如果需要检查它们，则需要在解析器中添加一行代码，并且需要在主函数中处理无效日期。

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