How to format strings in Scala?

Question

I need to print a formatted string containing scala.Long. java.lang.String.format() is incompatible with scala.Long (compile time) and RichLong (java.util.IllegalFormatConversionException)

Compiler warns about deprecation of Integer on the following working code:

val number:Long = 3243
String.format("%d", new java.lang.Long(number))

Should I change fomatter, data type or something else?

Answer 1

You can try something like:

val number: Long = 3243
"%d".format(number)

Answer 2

The format method in Scala exists directly on instances of String, so you don't need/want the static class method. You also don't need to manually box the long primitive, let the compiler take care of all that for you!

String.format("%d", new java.lang.Integer(number))

is therefore better written as

"%d".format(number)

Answer 3

@Bruno's answer is what you should use in most cases.

If you must use a Java method to do the formatting, use

String.format("%d",number.asInstanceOf[AnyRef])

which will box the Long nicely for Java.