Table of Contents
4-1: Variables
4-2: Values
In Scala, we have variables and values. The difference between the two is that variables can be reassigned while values cannot. When reassigning variables, however, we must use the same data type.
Open up the spark-shell and let’s start with a variable. We’ll create a variable called “thing1” and make it an “Int” with a value of “7”.
input
var thing1: Int = 7
output
thing1: Int =7
Now, let’s reassign it.
input
thing1 = 53
output
thing1: Int = 53
Note, however, we can not reassign a floating-point number to “thing1”. We will get an error if we try.
input
thing1 = 4.79
output
<console>:25: error: type mismatch;
found : Double(4.79)
required: Int
thing1 = 4.79
Now, let’s do values. We’ll create a string with my favorite city name of all-time “Sarmizegetusa”, the capital of Roman Dacia.
input
val city = “Sarmizegetusa”
output
city: String = Sarmizegetusa
Just for fun, we’ll try to reassign “Londinium” to “city”
input
city = “Londinium”
output
<console>:25: error: reassignment to val
city = “Londinium”
No surprise that we get an error since “values” can not be reassigned in Scala.
Part 1: Installation, Set-Up, and "Hello World"
Part 2: Data Types
Part 3: Arithmetic Operators
Part 4: Variables vs Values
Part 5: String Operations
Part 6: Tuples
Part 7: Lists
Part 8: Arrays
Part 9: Sets
Part 10: Maps
Part 11: Logical Operators
Part 12: If Statements
Part 13: For Loops
Part 14: While Loops
Part 15: Functions