Scala Variables and Data Types

Variable is a name which is used to refer memory location. You can create mutable and immutable variable in scala. Let's see how to declare variable.

Mutable Variable

You can create mutable variable using var keyword. It allows you to change value after declaration of variable.

var data = 100
data = 101 	// It works, No error.

In the above code, var is a keyword and data is a variable name. It contains an integer value 100. Scala is a type infers language so you don?t need to specify data type explicitly. You can also mention data type of variable explicitly as we have used in below.

Another example of variable

Immutable Variable

val data = 100
data = 101 // Error: reassignment to val

The above code throws an error because we have changed content of immutable variable, which is not allowed. So if you want to change content then it is advisable to use var instead of val.

Data Types in Scala

Data types in scala are much similar to java in terms of their storage, length, except that in scala there is no concept of primitive data types every type is an object and starts with capital letter. A table of data types is given below. You will see their uses further.

Data Type	Default Value	Size
Boolean	False	True or false
Byte	0	8 bit signed value (-2⁷ to 2⁷-1)
Short	0	16 bit signed value(-2¹⁵ to 2¹⁵-1)
Char	'\u0000'	16 bit unsigned Unicode character(0 to 2¹⁶-1)
Int	0	32 bit signed value(-2³¹ to 2³¹-1)
Long	0L	64 bit signed value(-2⁶³ to 2⁶³-1)
Float	0.0F	32 bit IEEE 754 single-precision float
Double	0.0D	64 bit IEEE 754 double-precision float
String	Null	A sequence of characters