function as variable, type---Golang

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The function in Go is also a variable, and we define the type of the variable by type. Functions that have the same parameters and the same return value belong to the same type.

By using a function as a variable of one type, we can pass this type of function as a value.

The following is a simple example.

Type functintyoe func (int) bool//declares a function type func isodd (integer int) bool {if integer%2 = = 0 {return False}return true}func IsEven (integer int) bool {if integer%2 = = 0 {return True}return false}//declared function type in this place as a parameter func filter (slice []int, F Fu Nctintyoe) []int {var result []intfor _, Value: = Range Slice {if f (value) {result = Append (result, value)}}return result} Func Test () {    slice: = []int {1, 2, 3, 4, 5, 7}    FMT. Println ("slice =", slice)    odd: = Filter (slice, isodd)    //function as a value to pass the    FMT. Println ("Odd Elements of Slice is:", ODD)    even: = Filter (slice, IsEven)  //function as a value to pass the    FMT. Println ("Even elements of Slice is:", even)}