# Mathutil
mathutil 包实现了一些数学计算的函数.
# 源码:
# 用法:
import (
"github.com/duke-git/lancet/v2/mathutil"
)
# Documentation
# Average
计算平均数. 可能需要对结果调用RoundToFloat方法四舍五入
函数签名:
func Average[T lancetconstraints.Number](numbers ...T) T
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Average(0, 0)) //0
fmt.Println(mathutil.Average(1, 1)) //1
avg := mathutil.Average(1.2, 1.4) //1.2999999998
roundAvg := mmathutil.RoundToFloat(avg, 1) // 1.3
}
# Exponent
指数计算（x的n次方）
函数签名:
func Exponent(x, n int64) int64
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Exponent(10, 0)) //1
fmt.Println(mathutil.Exponent(10, 1)) //10
fmt.Println(mathutil.Exponent(10, 2)) //100
}
# Fibonacci
计算斐波那契数列的第n个数
函数签名:
func Fibonacci(first, second, n int) int
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Fibonacci(1, 1, 1)) //1
fmt.Println(mathutil.Fibonacci(1, 1, 2)) //1
fmt.Println(mathutil.Fibonacci(1, 1, 3)) //2
fmt.Println(mathutil.Fibonacci(1, 1, 4)) //3
fmt.Println(mathutil.Fibonacci(1, 1, 5)) //5
}
# Factorial
计算阶乘
函数签名:
func Factorial(x uint) uint
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Factorial(0)) //1
fmt.Println(mathutil.Factorial(1)) //1
fmt.Println(mathutil.Factorial(2)) //2
fmt.Println(mathutil.Factorial(3)) //6
}
# Max
返回参数中的最大数
函数签名:
func Max[T lancetconstraints.Number](numbers ...T) T
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Max(0, 0)) //0
fmt.Println(mathutil.Max(1, 2, 3)) //3
fmt.Println(mathutil.Max(1.2, 1.4, 1.1, 1.4)) //1.4
}
# MaxBy
使用给定的比较器函数返回切片的最大值
函数签名:
func MaxBy[T any](slice []T, comparator func(T, T) bool) T
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
res1 := mathutil.MaxBy([]string{"a", "ab", "abc"}, func(v1, v2 string) bool {
return len(v1) > len(v2)
})
fmt.Println(res1) //abc
res2 := mathutil.MaxBy([]string{"abd", "abc", "ab"}, func(v1, v2 string) bool {
return len(v1) > len(v2)
})
fmt.Println(res2) //abd
res3 := mathutil.MaxBy([]string{}, func(v1, v2 string) bool {
return len(v1) > len(v2)
})
fmt.Println(res3) //“”
}
# Min
返回参数中的最小数
函数签名:
func Min[T lancetconstraints.Number](numbers ...T) T
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Min(0, 0)) //0
fmt.Println(mathutil.Min(1, 2, 3)) //1
fmt.Println(mathutil.Min(1.2, 1.4, 1.1, 1.4)) //1.1
}
# MinBy
使用给定的比较器函数返回切片的最小值
函数签名:
func MinBy[T any](slice []T, comparator func(T, T) bool) T
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
res1 := mathutil.MinBy([]string{"a", "ab", "abc"}, func(v1, v2 string) bool {
return len(v1) < len(v2)
})
fmt.Println(res1) //a
res2 := mathutil.MinBy([]string{"ab", "ac", "abc"}, func(v1, v2 string) bool {
return len(v1) < len(v2)
})
fmt.Println(res2) //ab
res3 := mathutil.MinBy([]string{}, func(v1, v2 string) bool {
return len(v1) < len(v2)
})
fmt.Println(res3) //“”
}
# Percent
计算百分比，保留n位小数
函数签名:
func Percent(val, total float64, n int) float64
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.Percent(1, 2, 2)) //1
fmt.Println(mathutil.Percent(0.1, 0.3, 2)) //33.33
}
# RoundToFloat
四舍五入，保留n位小数
函数签名:
func RoundToFloat(x float64, n int) float64
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.RoundToFloat(0, 0)) //0
fmt.Println(mathutil.RoundToFloat(0, 1)) //0
fmt.Println(mathutil.RoundToFloat(0.124, 2)) //0.12
fmt.Println(mathutil.RoundToFloat(0.125, 2)) //0.13
fmt.Println(mathutil.RoundToFloat(0.125, 3)) //0.125
}
# RoundToString
四舍五入，保留n位小数，返回字符串
函数签名:
func RoundToString(x float64, n int) string
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.RoundToString(0, 0)) //"0"
fmt.Println(mathutil.RoundToString(0, 1)) //"0.0:
fmt.Println(mathutil.RoundToString(0.124, 2)) //"0.12"
fmt.Println(mathutil.RoundToString(0.125, 2)) //"0.13"
fmt.Println(mathutil.RoundToString(0.125, 3)) //"0.125"
}
# TruncRound
截短n位小数（不进行四舍五入）
函数签名:
func TruncRound(x float64, n int) float64
例子:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/mathutil"
)
func main() {
fmt.Println(mathutil.TruncRound(0, 0)) //0
fmt.Println(mathutil.TruncRound(0, 1)) //0
fmt.Println(mathutil.TruncRound(0.124, 2)) //0.12
fmt.Println(mathutil.TruncRound(0.125, 2)) //0.12
fmt.Println(mathutil.TruncRound(0.125, 3)) //0.125
}