scala 方法调用

Scala方法调用 (Scala Method Invocation)

Method invocation is the legal and correct technique to call a method in Scala programming language. The methods of a class are usually accessed by using two methods.

方法调用是用Scala编程语言调用方法的合法且正确的技术。 通常使用两种方法来访问类的方法。

1. Object Creation

   对象创建

2. Inheritance

   遗产

We dynamically call methods of a class using the object of the class. the correct way of accessing the methods using object are:

我们使用类的对象动态调用类的方法。 使用object访问方法的正确方法是：

1)使用点运算符调用方法 (1) Invoking methods using dot operator)

While calling a method of a class from the object of the class we use the dot (.) operator. The correct and legal way of accessing the methods of a class in Scala using the dot operator is,

从类的对象调用类的方法时，我们使用点(。)运算符。 使用点运算符访问Scala中的类方法的正确合法方法是，

    object_name.method_name(parameters)

This is the most appropriate way of accessing the method of a class using an object. Else than this some ways can be used but are not ideal. These methods do not generate any error but are not correct ways to call the method. They are,

这是使用对象访问类的方法的最合适的方法。 除此以外，可以使用某些方法，但并不理想。 这些方法不会产生任何错误，但不是正确的方法。 他们是，

    object_name . method_name(parameters)
object_name. method_name(parameters) 
object_name . method_name (parameters)

Example code:

示例代码：

class car{
def sound(noise:String){
println(noise+" goes fast")
}
}
object MyClass {
def main(args: Array[String]) {
var newcar = new car();
newcar.sound("Lamborghini!")
newcar . sound("Honda!")
newcar .sound("Mercedes!")
newcar . sound ("BMW!")
} 
}

Output

输出量

Lamborghini! goes fast
Honda! goes fast
Mercedes! goes fast
BMW! goes fast

2)直接调用方法 (2) Invoking methods directly)

Calling a method from a class inherits the base class or in the same class. The correct and legal way to call the method is,

从类中调用方法将继承基类或同一类。 调用该方法的正确合法方法是：

    method_name(parameters)

Other than this other methods are also legal. Like,

除此之外，其他方法也是合法的。 喜欢，

    method_name (parameters)
method_name( parameters )
method_name ( parameters )

Example code:

示例代码：

object MyClass {
def sound(noise:String){
println(noise+" makes  noise")
}
def main(args: Array[String]) {
sound("Lamborghini!")
sound ( "Honda!")
sound ( "Mercedes!" )
} 
}

Output

输出量

Lamborghini! makes  noise
Honda! makes  noise
Mercedes! makes  noise

3)调用带有参数的方法 (3) Invoking methods with parameters)

When the method contains arguments and calling methods with parameters. For invoking methods with the argument we will separate the parameters using commas and single space.

当方法包含参数并使用参数调用方法时。 对于使用参数调用方法，我们将使用逗号和单个空格分隔参数。

    object_name.method_name(parameter1, parameter2)

Other legal methods that are not correct but does not compile to an error,

其他不正确但无法编译为错误的合法方法，

    object_name. method_name(parameter1, parameter2)
object_name.method_name (parameter1, parameter2)
object_name.method_name( parameter1 , parameter2 )
object_name. method_name ( parameter1 , parameter2 )

Example code:

示例代码：

class  calculator{
def add(a:Int , b:Int){
println("The sum of "+a+" and "+b+" is "+(a+b))
}
}
object MyClass {
def main(args: Array[String]) {
var calc = new calculator();
calc.add(12,34)
calc. add(1,434)
calc.add (2,3)
calc.add(15, 4)
calc. add ( 232,314 )
} 
}

Output

输出量

The sum of 12 and 34 is 46
The sum of 1 and 434 is 435
The sum of 2 and 3 is 5
The sum of 15 and 4 is 19
The sum of 232 and 314 is 546

4)调用特殊方法 (4) Invoking special method)

When a method in Scala does not accept any argument. So, while invoking no arguments are passed which make the parentheses optional. Without parenthesis, the code becomes much more readable and also easy the programmers work.

当Scala中的方法不接受任何参数时。 因此，在调用时，不会传递使括号成为可选参数的参数。 没有括号，代码变得更具可读性，并且使程序员易于工作。

Both this is legal and correct ways to invoke a method that does not take any parameter.

这是调用不带任何参数的方法的合法方法和正确方法。

    object_name.method_name()
object_name.method_name

Example code:

示例代码：

class car{
def sound(){
println("Broom Broom Brooooom!!!!!")
}
}
object MyClass {
def main(args: Array[String]) {
var newcar = new car();
newcar.sound()
newcar.sound
}
}

Output

输出量

Broom Broom Brooooom!!!!!
Broom Broom Brooooom!!!!!

翻译自: https://www.includehelp.com/scala/method-invocation-in-scala.aspx

scala 方法调用