Convert minutes to hours scala - scala

Question

I have a number in minutes, for example:
Int totalminutes= 342
I want to dispaly it like this:
5h:42m:..s
I did a scala function to convert the minute to hour and return HH:MM:SS
scala> def convertSeconds(input:Int):String ={
| val totalMinutes = input/60
| val seconds = input%60
| val minutes = totalMinutes%60
| val hours = totalMinutes%60
|
| return "%sh:%sm:%ss".format(hours,minutes,seconds)
| }
convertSeconds: (input: Int)String
I did my tests:
scala> convertSeconds(120) // 120 minutes
res22: String = 2h:2m:0s // why it add 2 minutes
scala> convertSeconds(60) // 60 minutes
res23: String = 1h:1m:0s // adding 1 minute
scala> convertSeconds(36) // 36 minutes
res24: String = 0h:0m:36s // I want to return 0h:30m:06s
The solution is:
scala> def convertSeconds(input:Int):String ={
//val totalMinutes = input/60
//val seconds = input/60%60
val minutes = input%60
val hours = input/60
return "%sh:%sm".format(hours,minutes)
}
convertSeconds: (input: Int)String
scala> convertSeconds(36)
res57: String = 0h:36m
scala> convertSeconds(120)
res58: String = 2h:0m
scala> convertSeconds(122)
res59: String = 2h:2m
scala> convertSeconds(2166)
res60: String = 36h:6m

Answer 1

Your function is supposed to be like this and you pass seconds not minutes:
def convertSeconds(input:Int):String ={
val hours = input/3600
val minutes = (input-hours*3600)/60
val seconds = input%3600-minutes*60
"%sh:%sm:%ss".format(hours,minutes,seconds)
}
If you want to pass minutes, the function should be something like this, I named it convertMinutes, and your seconds will zero, and you can get in your prescribed display by this code:
def convertMinutes(input:Int):String ={
val hours = input/60
val minutes = input-hours*60
"%sh:%sm:%ss".format(hours,minutes,"..")
}
In Scala REPL:
scala> convertSeconds(7523)
res4: String = 2h:5m:23s
scala> convertSeconds(9523)
res5: String = 2h:38m:43s
scala> convertSeconds(3724)
res6: String = 1h:2m:4s
scala> convertMinutes(342)
res10: String = 5h:42m:..s

Answer 2

I am not sure if you need a separate function to achieve this.
Scala already gives a library to do that
scala> val secs = 62
secs: Int = 62
scala> import scala.concurrent.duration._
scala> val inTime = Duration(secs,SECONDS)
inTime: scala.concurrent.duration.FiniteDuration = 62 seconds
scala> "%02d:%02d:%02d".format(inTime.toHours,inTime.toMinutes%60,inTime.toSeconds%60)
res8: String = 00:01:02
EDIT-1: What this does not handle is if you pass a number >= 86400 (total seconds in a day)

Answer 3

In Java, trusting you to translate yourself:
int totalminutes = 342;
Duration dur = Duration.ofMinutes(totalminutes);
String display = String.format("%dh:%02dm:%02ds",
dur.toHours(), dur.toMinutesPart(), dur.toSecondsPart());
System.out.println(display);
This prints:
5h:42m:00s
If had a number of seconds instead, use Duration.ofSeconds instead.
Don’t do the calculation yourself. It’s error-prone and it will require your reader to take some time to convince herself/himself that your calculation is correct. Instead let the library methods do the calculations, even when they seem trivial.
What went wrong in your code?
It’s been said already: You used
val hours = totalMinutes%60
This should have been a division:
val hours = totalMinutes / 60
It’s easier than you might expect to make such an error. For comparison you don’t that easily call toMinutesPart when you intended toHours, and if you still do, it’s easier to spot the bug.