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This article mainly introduces "what is a Scala closure". In daily operation, I believe many people have doubts about what a Scala closure is. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful for you to answer the doubts about "what is a Scala closure?" Next, please follow the editor to study!

A closure is a function and the return value depends on one or more variables declared outside the function.

Any variable in the corresponding scope can be used in the body of the function.

Generally speaking, a closure can be simply thought of as another function that can access local variables in a function.

Normal function:

Val multiplier = (i:Int) = > I * 10

There is a variable I in the body of the function, which is used as an argument to the function.

Val multiplier = (i:Int) = > I * factor

There are two variables in multiplier: I and factor. One of the I is the formal argument of the function, and when the multiplier function is called, I is assigned a new value. However, factor is not a formal parameter, but a free variable. Consider the following code:

Var factor = 3 val multiplier = (i:Int) = > I * factor

Here we introduce a free variable factor, which is defined outside the function.

The function variable multiplier defined in this way becomes a "closure" because it refers to the variable defined outside the function, and the process of defining this function is to capture the free variable to form a closed function.

Object Test {def main (args: Array [String]) {println ("muliplier (1) value =" + multiplier (1)) println ("muliplier (2) value =" + multiplier (2))} var factor = 3 val multiplier = (i:Int) = > I * factor}

At this point, the study of "what is a Scala closure" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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