Scala Loops ( For loop, while loop and do While loop )

 

For Loop :

Syntax :

for (condition) {

  //-- Code to Run 

  //-- Code to Run

}

 

Rule :

1. Check condition
2. If condition is True then run code withing for loop else exit 

 

Example:

scala> val hadoopguru = Range(1, 10)
hadoopguru: scala.collection.immutable.Range = Range(1, 2, 3, 4, 5, 6, 7, 8, 9)

 

scala> for (h <- hadoopguru) {
     |     println(s"Item : ${h}")
     | }
Item : 1
Item : 2
Item : 3
Item : 4
Item : 5
Item : 6
Item : 7
Item : 8
Item : 9

While Loop :

Syntax :

while (condition) {

  //-- Code to Run 

  //-- Code to Run

}

 

Rule :

1. Check condition
2. If condition is True then run code within while loop else if condition is False then exit 

 

Example: 

scala> var h = 0

h: Int = 0

scala> while (h < 10) {

     |   h = h+1

     |   println(s"Item : ${h}")

     | }

Item : 1

Item : 2

Item : 3

Item : 4

Item : 5

Item : 6

Item : 7

Item : 8

Item : 9

Item : 10

Note : While loop continue to run until condition is True. Be careful not to get into infinite loop.

do while Loop :

Syntax :

do {

     //-- Code to Run 

     //-- Code to Run

} while (condition);

 

Rule :

1. Run code at least once then Check condition

2. If condition is True then run code within while loop again else if condition is False then exit 

 

Example: 

scala> var h = 0

h: Int = 0

scala> do {

     |      h = h+1

     |      println(s"Item : ${h}")

     | } while (h < 0);

Item : 1

Note : do While loop is similar to while loop except code block runs at least once.

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