79 lines
1.6 KiB
Go
79 lines
1.6 KiB
Go
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package main
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// extra resource: https://go.dev/doc/tutorial/generics
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import (
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"fmt"
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"golang.org/x/exp/constraints"
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)
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// interfaces with type elements couldn't be used anywhere other than type paramaters
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type Number interface {
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int64 | float64
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}
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type Myint interface {
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int64
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}
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func SumInt[K comparable, V Myint](m map[K]V) V {
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var s V
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for _, v := range m {
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s += v
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}
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return s
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}
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func SumIntFloat[K comparable, V Number](m map[K]V) V {
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var s V
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for _, v := range m {
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s += v
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}
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return s
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}
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func SumAll[K comparable, V constraints.Ordered](m map[K]V) V {
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var s V
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for _, v := range m {
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s += v
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}
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return s
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}
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func main2() { // change main2 to main befor testing !!!
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fmt.Println("Go functions can be written to work on multiple types using type parameters")
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fmt.Println("square bracked types after function names are type paramaters")
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fmt.Println("You can create type paramaters with keyword `comparable`(for comparable types), `any` for any type or other type name/s.")
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fmt.Println("See differences between SumInt, SumIntFloat and SumAll")
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fmt.Println("Please note down map keys should be comparable because of default map behaviour")
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ints := map[string]int64{
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"first": 1,
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"second": 2,
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"third": 3,
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}
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floats := map[string]float64{
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"first": 1.23,
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"second": 2.3123,
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"third": 3,
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}
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strings := map[string]string{
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"first": "str1",
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"second": "str2",
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"third": "str3",
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}
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fmt.Println(SumInt(ints))
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// fmt.Println(SumInt(floats)) // error
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fmt.Println(SumIntFloat(ints))
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fmt.Println(SumIntFloat(floats))
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// fmt.Println(SumIntFloat(strings)) // error
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fmt.Println(SumAll(ints))
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fmt.Println(SumAll(floats))
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fmt.Println(SumAll(strings))
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}
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