I want to get current date in Scala as a String. For example, today current date is 5th Jan. I want to store it as a new variable dynamically as below.
val currdate : String = “20220105”
When I am using val currdate = Calendar.getInstance.getTime then am not getting output in desired format as above.
This is how it's done using the contemporary java.time library.
import java.time.LocalDate
import java.time.format.DateTimeFormatter
val currdate: String =
LocalDate.now.format(DateTimeFormatter.ofPattern("yyyyMMdd"))
Older utilities like Calendar and SimpleDate still work (mostly) but should be avoided.
Why do you need it as String?
For a Spark query you could use java.sql.Timestamp directly.
This how you get it:
import java.sql.Timestamp
import java.text.SimpleDateFormat
import java.time.Instant
val now: Timestamp =
Timestamp.from(Instant.now())
If you really want a formatted String:
val asString =
new SimpleDateFormat("yyyyMMdd").format(now)
SimpleDateFormat is old and not thread-safe but should do the job.
Related
Trying to parse a date string, 2020-10-20 19:36:00 using this Scala code.
val DATE_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
val date = LocalDate.parse("2020-10-20 19:36:00", DATE_FORMAT).atStartOfDay(ZoneId.systemDefault())
However when I println(date) I get this line 2020-10-20T00:00+02:00[Europe/Stockholm]
which is only including the date without hours, minutes... What method should I use instead to obtain a ZonedDateTime object containing all information in my date string.
I solved this issue using this piece of code.
val DATE_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneId.systemDefault())
val date = ZonedDateTime.parse(x,DATE_FORMAT)
I added the ZoneId to the pattern, making it possible to use the ZoneDateTime.parse(...) method
How can I convert the dd/mm/yyyy to yyyymmdd format and also
dd/m/yyyy to yyyymmdd format by using joda time in Scala.
am using this dependency
"joda-time" % "joda-time" % "2.9.9",
This answer already answers your question in Java, but here it is translated into Scala:
import org.joda.time.DateTime
import org.joda.time.format.{DateTimeFormat, DateTimeFormatter}
// define original date format
val originalFormat: DateTimeFormatter = DateTimeFormat.forPattern("dd/MM/yyyy")
val input: DateTime = originalFormat.parseDateTime("02/09/2017")
// define new format
val newFormat: DateTimeFormatter = DateTimeFormat.forPattern("yyyyMMdd")
val output: String = newFormat.print(input) // 20170902
This code will already account for missing a leading 0 from your date (ie it will see 02/9/2017 and 2/9/2017 as the same thing). It will not predict missing parts of the year though, so 2/9/17 will be outputted as 00170902 instead of 20170902.
As the answer I linked to earlier mentions though, you can just use java.time to do the same thing:
import java.time.LocalDate
import java.time.format.DateTimeFormatter
val originalFormat = DateTimeFormatter.ofPattern("dd/MM/yyyy")
val input = LocalDate.parse("02/09/2017", originalFormat)
val newFormat = DateTimeFormatter.ofPattern("yyyyMMdd")
val output = input.format(newFormat)
import org.joda.time.DateTime
import org.joda.time.format._
val fmt = DateTimeFormat.forPattern("dd/mm/yyyy")
val dt = fmt.parseDateTime("02/02/2017")
val fmt2 = DateTimeFormat.forPattern("yyyymmdd")
fmt2.print(dt)
I want to get for example a string of the current time: "20180122_101043". How can I do this?
I can create a val cal = Calendar.getInstance() but I'm not sure what to do with it after.
LocalDateTime is what you might want to use,
scala> import java.time.LocalDateTime
import java.time.LocalDateTime
scala> LocalDateTime.now()
res60: java.time.LocalDateTime = 2018-01-22T01:21:03.048
If you don't want default LocalDateTime format which is basically ISO format without zone info, you can apply DateTimeFormatter as below,
scala> import java.time.format.DateTimeFormatter
import java.time.format.DateTimeFormatter
scala> DateTimeFormatter.ofPattern("yyyy-MM-dd_HH:mm").format(LocalDateTime.now)
res61: String = 2018-01-22_01:21
Related resource - How to parse/format dates with LocalDateTime? (Java 8)
Calendar is not the best choice here. Use:
java.util.Date + java.text.SimpleDateFormat if you have java 7 or below
new SimpleDateFormat("YYYYMMdd_HHmmss").format(new Date)
java.time.LocalDateTime + java.time.format.DateTimeFormatter for java 8+
LocalDateTime.now.format(DateTimeFormatter.ofPattern("YYYYMMdd_HHmmss"))
You can make use of Java 8 Date/Time API:
import java.time.LocalDateTime
import java.time.format.DateTimeFormatter
val format = "yyyyMMdd_HHmmss"
val dtf = DateTimeFormatter.ofPattern(format)
val ldt = LocalDateTime.of(2018, 1, 22, 10, 10, 43) // 20180122_101043
ldt.format(dtf)
To get the current time, use LocalDateTime.now().
You may use the java.time library. For instance:
import java.time
val s: String = time.LocalDateTime.now().toString
println(s)
gives 2021-04-23T14:13:01.163869. Then you need to manipulate the string, e.g.
time.LocalDateTime.now().toString.replace("T","_").replace("-","").replace(":","")
for 20210423_141639.769222.
Suppose my date format is 21/05/2017 then the output will be SUN.
How can I get the day given a date?
import java.time.LocalDate
import java.time.format.DateTimeFormatter
val df = DateTimeFormatter.ofPattern("dd/MM/yyyy")
val dayOfWeek = LocalDate.parse("21/05/2017",df).getDayOfWeek
You can use SimpleDateFormat as illustrated below:
import java.util.Calendar
import java.text.SimpleDateFormat
val now = Calendar.getInstance.getTime
val date = new SimpleDateFormat("yyyy-MM-dd")
date.format(now)
res1: String = 2017-05-20
val dowInt = new SimpleDateFormat("u")
dowInt.format(now)
res2: String = 6
val dowText = new SimpleDateFormat("E")
dowText.format(now)
res3: String = Sat
[UPDATE]
As per comments below, please note that SimpleDateFormat isn't thread-safe.
You can also use nscala-time which is a Scala wrapper for Java's joda-time which is a datetime library with a ton of functionality.
import com.github.nscala_time.time.Imports._
val someDate =(newDateTime).withYear(2017)
.withMonthOfYear(5)
.withDayOfMonth(21)
someDate.getDayOfWeek
res7: Int = 7
Now you need to know the mapping between integer days of the week and names. Here, 7 corresponds to Sunday.
I have a date variable
var date: Date = new Date()
then I have converted this date to String:
var dateStr = date.toString()
now I need to convert back this String to date.
I have tried both:
1:
var stringToDate: Date = date2Str.asInstanceOf[Date]
and 2:
stringToDate: Date = new SimpleDateFormat("dd.MM.yyyy").parse(dateStr);
But in both case I got the error:
java.lang.ClassCastException:
java.lang.String cannot be cast to java.util.Date
I see a couple of problems in your code, but this works fine:
scala> val format = new java.text.SimpleDateFormat("dd-MM-yyyy")
format: java.text.SimpleDateFormat = java.text.SimpleDateFormat#9586200
scala> format.format(new java.util.Date())
res4: java.lang.String = 21-03-2011
scala> format.parse("21-03-2011")
res5: java.util.Date = Mon Mar 21 00:00:00 CET 2011
Starting Scala 2.11, targeting Java 8, the java.time Date Time API can be used:
import java.time.LocalDate
import java.time.format.DateTimeFormatter
val dtf = DateTimeFormatter.ofPattern("dd-MM-yyyy")
LocalDate.now().format(dtf) // "06-07-2018"
LocalDate.parse("06-07-2018", dtf) // java.time.LocalDate = 2018-07-06
Note that:
This is part of the standard library (no need for third party dependencies)
This is meant to replace the old java.util.Date/SimpleDateFormat api.
This is also supposed to replace the widely used joda-time library:
Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project.
And by association nscala-time which is a wrapper around joda-time.
Your first try should give you a ClassCastException because you cannot cast.aString to a Date. the second try does not seem to be using the right format that Date.toString() prints. The toString method of java.utility.Date returns a String in the format specified in the javadoc.
using nscala-time the following worked for me :
import com.github.nscala_time.time._
import com.github.nscala_time.time.Imports._
val ysterday= (DateTime.now- 1.days).toString(StaticDateTimeFormat.forPattern("yyyyMMdd"))