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Strings and Other Literals

Strings and Other Literals

In the following lesson, you will be introduced to literals.

We'll cover the following...

By now, you must have noticed that we haven’t discussed strings. Strings do not fall under anyVal in the data type hierarchy. This raises the question: what are strings?

The single word answer is ‘literals’.

Literals

A literal is defined as taking anything in its most usual and basic sense. Mapping this onto computer programming, literals are fixed values appearing directly as is in the source code. For example, “Hello World”, 55, and ‘A’ are all literals.

String Literals

Strings literals are a combination of characters surrounded by double quotation marks. The syntax for declaring a variable of type String is the same as declaring a variable of any basic value type.

Scala
val stringLiteral: String = "Hello"
// Driver Code
println(stringLiteral)

Integer Literals

Integer Literals are used with the value types Long, Int, Short, and Byte and come in two forms: decimal and hexadecimal. Decimal numbers have a base 1010 while hexadecimal numbers have a base 1616. The way an integer literal begins indicates the base of the number. If the number begins with a 00x or 00X, it is hexadecimal and may contain the numbers from 00 through 99 as well as upper or lowercase letters from A to F. Numbers that do not start with 00x or 00X are decimal by default.

Scala
val hex: Int = 0x0F5
val dec: Int = 245
val hex1: Long = 0x0A3DE5L //The L at the end is for Long
val dec1: Long = 671205L
// Driver Code
println(hex)
println(dec)
println(hex1)
println(dec1)

One thing to remember is that Scala will always print an integer literal as decimal regardless of how it is declared.

Floating-Point Literals

Floating-point literals are used with Double and Float. They are made up of decimal digits and have the option of adding exponents using either an e or E followed by the exponent.

Scala
val floatLiteral: Float = 1.2345F // The F at the end is for Float
val somethingBigger: Double = 1.2345e1
val evenBigger: Double = 1.2345e4
// Driver Code
println(floatLiteral)
println(somethingBigger)
println(evenBigger)

Character Literals

Character literals are used with Char and are made up of a single Unicode character surrounded by single quotation marks.

Scala
val charLiteral: Char = 'A'
val smile: Char = '☺'
// Driver Code
println(charLiteral)
println(smile)

Escape sequences, as shown in the table below, also represent character literals.

Literal Meaning
\n linefeed
\b backspace
\t tab
\f form feed
\r carriage return
\" double quote
\’ single quote
\\ backslash

Let’s look at some examples:

Scala
println("separate\nlines")     //using \n to end the line
println("tab\tbetween\twords") //using \t to insert a tab
println('\\')                  //using \\ to print a backslash
println('\'')                  //using \' to print a single quotation mark   
println('\"')                  //using \" to print a double quotation mark

Boolean Literals

Boolean literals are used with Boolean. They are of two types: true and false.

Scala
val theTruth: Boolean = true
val aLie: Boolean = false
// Driver Code
println(theTruth)
println(aLie)

Let’s complete our discussion on variables and types with type inference in the next lesson.