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Scala IF ... ELSE statement

Scala IF ... ELSE statement block of code is determined by the results of one or more statements of (True or False).

The following figure can be a simple understanding of the execution of the conditional statement:


if statement

if there is a block of statements and statements following Boolean expressions.

grammar

Syntax if the statement is as follows:

if(布尔表达式)
{
   // 如果布尔表达式为 true 则执行该语句块
}

If the Boolean expression is true then execute a block of statements inside the curly braces, otherwise skip a block of statements inside the curly braces, the statement is executed after the block braces.

Examples

object Test {
   def main(args: Array[String]) {
      var x = 10;

      if( x < 20 ){
         println("x < 20");
      }
   }
}

Running instance »

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
x < 20

if ... else statement

After the if statement can be followed by else statements, statements can be executed within the block else to false when the Boolean expression.

grammar

if ... else syntax is as follows:

if(布尔表达式){
   // 如果布尔表达式为 true 则执行该语句块
}else{
   // 如果布尔表达式为 false 则执行该语句块
}

Examples

object Test {
   def main(args: Array[String]) {
      var x = 30;

      if( x < 20 ){
         println("x 小于 20");
      }else{
         println("x 大于 20");
      }
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
x 大于 20

if ... else if ... else statement

After the if statement can be followed else if ... else statement, in the case of multiple conditional statements useful.

grammar

if ... else if ... else syntax is as follows:

if(布尔表达式 1){
   // 如果布尔表达式 1 为 true 则执行该语句块
}else if(布尔表达式 2){
   // 如果布尔表达式 2 为 true 则执行该语句块
}else if(布尔表达式 3){
   // 如果布尔表达式 3 为 true 则执行该语句块
}else {
   // 如果以上条件都为 false 执行该语句块
}

Examples

object Test {
   def main(args: Array[String]) {
      var x = 30;

      if( x == 10 ){
         println("X 的值为 10");
      }else if( x == 20 ){
         println("X 的值为 20");
      }else if( x == 30 ){
         println("X 的值为 30");
      }else{
         println("无法判断 X 的值");
      }
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
X 的值为 30

if ... else statement nested

Nested if ... else statements can be embedded in one or more of if statements within the if statement.

grammar

Nested if ... else statement syntax is as follows:

if(布尔表达式 1){
   // 如果布尔表达式 1 为 true 则执行该语句块
   if(布尔表达式 2){
      // 如果布尔表达式 2 为 true 则执行该语句块
   }
}

else if ... else statement nested similar nested if ... else statement.

Examples

object Test {
   def main(args: Array[String]) {
        var x = 30;
        var y = 10;

         if( x == 30 ){
            if( y == 10 ){
            println("X = 30 , Y = 10");
         }
      }
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
X = 30 , Y = 10