Scala: For Loop

The for loop is an efficient way to write a loop that needs to be repeated a certain number of times. A for loop can be written in various ways in Scala, as follows:

Syntax − for loop with ranges

The simplest syntax.

for( var x <- Range ){
   statement(s);
}

examples:

for( a <- 1 to 10){

for( a <- 1 to 3; b <- 1 to 3){

for( a <- 1 until 10){

Syntax − for Loop with Collections

for( var x <- List ){
   statement(s);
}

Syntax − for loop with Filters

for( var x <- List
      if condition1; if condition2...
   ){
   statement(s);
}

Syntax − for loop with yield

"For" loop return values can be stored in variables or returned through functions. Yield is used as a prefix to the body of 'for' Loop.

var retVal = for{ var x <- List
   if condition1; if condition2...
}
yield x

example:

var retVal = for{ a <- numList if a != 3; if a < 8 }yield a