Question

我有从文件夹名称派生的字符串列表。

List(20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625)

我想将整个元素列表转换为Local Date类型格式。我用Scala语言编写代码。任何人都可以帮助我吗？

Answer 1

您可以尝试以下代码：

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

val inputTimes = List(20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625)
val dtf = DateTimeFormatter.ofPattern("yyyyMMdd")
val dates = inputTimes.map(date => LocalDate.parse(date.toString, dtf))
dates

您还可以指定新的区域设置

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

val inputTimes = List(20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625)
val dtf = DateTimeFormatter.ofPattern("yyyyMMdd")
val dtfWithLocale = dtf.withLocale(java.util.Locale.US)
val dates = inputTimes.map(date => LocalDate.parse(date.toString, dtfWithLocale))
dates

结果是

dates。

Answer 2

如果您尝试将其转换为Undefined symbols for architecture x86_64: "_PyUnicode_DecodeFSDefault", referenced from: MainWindow::pythonTry(QString&) in mainwindow.o格式，则可以执行此类操作

YYYY-MM-DD

Answer 3

要将字符串转换为java.util.Date，您可以使用：

val df = new SimpleDateFormat("yyyyMMdd")
list.map(df.parse(_))

对于LocalDate使用

list.map(LocalDate.parse(_, DateTimeFormatter.ofPattern("yyyyMMdd")))

Answer 4

分裂是粗略的实施。但是应该工作

  def split(i: Int): LocalDate = {
    val date = i % 100
    val rem = i / 100
    val mon = rem % 100
    val r = rem / 100
    LocalDate.of(r, mon, date)
  }

  def main(args: Array[String]): Unit = {
    val l = List(20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625, 20170625)
    val x = l.map(split)
  }

Answer 5

首先，我编写了将字符串转换为LocalDateTime格式的函数，如下所示

import java.time.LocalDateTime
import java.time.format.DateTimeFormatter
private def stringToDateTime(datetime:String): LocalDateTime ={
        val pattern:String="yyyyMMdd"
        LocalDateTime.parse(datetime, DateTimeFormatter.ofPattern(pattern))}

然后我将值与List of elements映射如下

def mapDateTime(list:List[String]):List[LocalDateTime] ={
list.map(datetime => stringToDateTime(datetime))}

然后我最终得到以下结果

List[java.time.LocalDateTime] = List(2017-06-25, 2017-06-25, 2017-06-25, 2017-06-25, 2017-06-25, 2017-06-25, 2017-06-25, 2017-06-25)

如何在Scala中将String列表转换为LocalDate类型格式

5 个答案: