Scala Cheatsheet

Scala (/ˈskɑːlɑː/ SKAH-lah) is a strong statically typed general-purpose programming language which supports both object-oriented programming and functional programming. Designed to be concise, many of Scala’s design decisions are aimed to address criticisms of Java.

Sample program in Scala

object HelloWorld {
	def main(args: Array[String]): Unit = {
	println("Hello, World!")
	}
}

• object : Object is a instance of a class. In Scala, everything is considered as objects.
• def : def is used for function declaration
• main : entry point of the program
• println : prints data to the console.
• // : Single line comment
• /* Multi
  Line
  comment */

Data types in Scala

Variables in Scala

var varName = value
val  varName = value
varName = value
var varName : DataType = value

Operators in Scala

Conditional Statements

1. If

if(conditional-expression)
{
    //code
}

2. If-else

if(conditional-expression)
{
    //code
} else {
    //code
}

3. If-else-if ladder

if(conditional-expression-1)
{
    //code
} else if(conditional-expression-2) {
    //code
} else if(conditional-expression-3) {
    //code
}
....
else {
    //code
}

Loops

1. For

for(var <- range){  
//code  
} 

2. For loop Using until

for( var <- initialValue until maxValue ){  
    //code  
}

3. For loop filtering

for( var <- initialValue until maxValue if condition){  
  //code
}

4. For loop for collections like lists, sequence etc

for( varName <- Collections){             
  //code
}

5. While

while(condition){  
//code 
}  

6. Do-while

do{  
//code 
}while(condition); 

Arrays in Scala

Array is a collection of similar data which is stored in continuous memory addresses.

Declaring 1-D array

var arrayName:Array[datatype] = new Array[datatype](size)

//or

var arrayName = new Array[datatype](size)

Declaring 2-D array

var arrName = ofDim[datatype](rowsize,colSize)

Example

 var arr1 = Array(1, 2, 3, 4, 5)

Functions in Scala

How to declare a Function

def functionName ([argumentsList]) : [return type]

How to define a Function

def functionName ([argumentsList]) : [return type] [=] {
   // code
   return [expr]
}

How to call a Function

function_name (argumentsList)

If you have quires and suggestions put them in the comments.