查找两个日期之间的日期答案

【问题标题】：Find dates between two dates scala查找两个日期之间的日期
【发布时间】：2020-07-19 10:17:49
【问题描述】：

我正在尝试提取两个日期之间的日期。

如果我的输入是：开始日期：2020_04_02 结束日期：2020_06_02

输出应该是 - List("2020_04_02","2020_04_03", "2020_04_04", "2020_04_05", "2020_04_06")

到目前为止我已经尝试过：

   val beginDate = LocalDate.parse(startDate, formatter)
   val lastDate = LocalDate.parse(endDate, formatter)
   beginDate.datesUntil(lastDate.plusDays(1)).iterator().asScala.map(date => formatter.format(date)).toList


 import java.time.format.DateTimeFormatter
 private def formatter = DateTimeFormatter.ofPattern("yyyy_MM_dd")

但我认为它甚至可以以更精致的方式完成

【问题讨论】：

标签： scala scala-collections

【解决方案1】：

您所做的是正确的，但您的结束日期与您的预期不符：


    import java.time.format.DateTimeFormatter
    import java.time.LocalDate
    import scala.jdk.CollectionConverters._

    private def formatter = DateTimeFormatter.ofPattern("yyyy_MM_dd")
    val startDate = "2020_04_02"
    val endDate1 = "2020_04_06" // "2020_06_02"
    val endDate2 = "2020_06_02"
    val beginDate = LocalDate.parse(startDate, formatter)
    val lastDate1 = LocalDate.parse(endDate1, formatter)
    val lastDate2 = LocalDate.parse(endDate2, formatter)
    val res1 =  beginDate.datesUntil(lastDate1.plusDays(1)).iterator().asScala.map(date => formatter.format(date)).toList
    val res2 =  beginDate.datesUntil(lastDate2.plusDays(1)).iterator().asScala.map(date => formatter.format(date)).toList

    println(res1) // List(2020_04_02, 2020_04_03, 2020_04_04, 2020_04_05, 2020_04_06)
    println(res2) // List(2020_04_02, 2020_04_03, 2020_04_04, 2020_04_05, 2020_04_06 ... 2020_05_31, 2020_06_01, 2020_06_02)

【讨论】：

【解决方案2】：

我对此并不感到非常自豪，但我以前也这样做过：

val start = LocalDate.of(2020,1,1).toEpochDay
val end = LocalDate.of(2020,12,31).toEpochDay
val dates = (start to end).map(LocalDate.ofEpochDay(_).toString).toArray

你最终得到：

dates: Array[String] = Array(2020-01-01, 2020-01-02, ..., 2020-12-31)

【讨论】：

【解决方案3】：

此函数将返回 List[String]。

import java.time.format.DateTimeFormatter
import java.time.LocalDate

  val dt1 = "2020_04_02"
  val dt2 = "2020_04_06"

  def DatesBetween(startDate: String,endDate: String) : List[String] = {
    def ConvertToFormat = DateTimeFormatter.ofPattern("yyyy_MM_dd")
    val sdate = LocalDate.parse(startDate,ConvertToFormat)
    val edate = LocalDate.parse(endDate,ConvertToFormat)
    val DateRange = sdate.toEpochDay.until(edate.plusDays(1).toEpochDay).map(LocalDate.ofEpochDay).toList
    val ListofDateRange = DateRange.map(date => ConvertToFormat.format(date)).toList
    ListofDateRange
  }

  println(DatesBetween(dt1,dt2))

【讨论】：