Now that you’ve seen strings and integers, a next good thing to know is that Scala comes with the following built-in numeric data types:
ByteShortIntLongFloatDouble
And when you’re working with extremely large numbers you can also use:
BigIntBigDecimal
Scala’s numeric data types
As a practical matter, until numbers get very large, most programmers generally use integers (Int) and double values (Double). Because of that, these are the defaults in Scala, as you can see in the REPL:
scala> val x = 42
val x: Int = 42
scala> val y = 42.0
val y: Double = 42.0When I create x, Scala is smart enough to implicitly know that x is an Int, and when I create y, Scala also implicitly infers that it is a Double.
On the rare occasions that you might need to use the other numeric data types, declare them when you create your variables, like this:
val a: Byte = 1
val b: Long = 1
val c: Short = 1
val d: Float = 1.0
// you can also declare Int and Double this way,
// though it isn’t necessary:
val e: Int = 1
val f: Double = 1.0Scala 3 also lets you declare numbers using underscore characters to make them more readable:
val a = 1_000 // Int
val b = 1_000_000 // Int
val c = 1_000_000L // Long (created with the 'L' after the number)
val d = 1_234.56 // DoubleThis is a really useful feature when you’re working with large numbers.
BigInt and BigDecimal
When you need to create really, really large numbers, use the BigInt and BigDecimal data types:
val a = BigInt(1_234_567_890_123_456L)
val b = BigDecimal(123_456_789.012)Use BigInt when you need integer-type numbers that are larger than Long, and BigDecimal when using very large floating-point numbers. Some developers also use BigDecimal for working with currency.
Scala data type sizes
For your reference, this table provides details about Scala’s data types:
Data Type Definition
Boolean true or false
Byte 8-bit signed two’s complement integer
(-2^7 to 2^7-1, inclusive)
-128 to 127
Short 16-bit signed two’s complement integer
(-2^15 to 2^15-1, inclusive)
-32,768 to 32,767
Int 32-bit two’s complement integer
(-2^31 to 2^31-1, inclusive)
-2,147,483,648 to 2,147,483,647
Long 64-bit two’s complement integer
(-2^63 to 2^63-1, inclusive)
-9,223,372,036,854,775,808 to +9,223,372,036,854,775,807
Float 32-bit IEEE 754 single-precision float
1.40129846432481707e-45 to 3.40282346638528860e+38
(positive or negative)
Double 64-bit IEEE 754 double-precision float
4.94065645841246544e-324 to 1.79769313486231570e+308
(positive or negative)
Char 16-bit unsigned Unicode character
(0 to 2^16-1, inclusive)
0 to 65,535
String a sequence of Char valuesFor more details on BigInt and BigDecimal, see their Scaladoc pages:
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Exercises
The exercises for this lesson are available here.
