F# - 运算符

运算符是一个符号，告诉编译器执行特定的数学或逻辑操作， F#内置丰富的运算符，并提供以下类型的运算符-

• 算术运算符
• 比较运算符
• 布尔运算符
• 按位运算符

算术运算符

下表显示了F#语言支持的所有算术运算符。假设变量A=10，变量B=20，则-

无涯教程网

let a : int32 = 21
let b : int32 = 10

let mutable c = a + b
printfn "Line 1 - Value of c is %d" c

c <- a - b;
printfn "Line 2 - Value of c is %d" c

c <- a * b;
printfn "Line 3 - Value of c is %d" c

c <- a / b;
printfn "Line 4 - Value of c is %d" c

c <- a % b;
printfn "Line 5 - Value of c is %d" c

编译并执行程序时，将产生以下输出-

Line 1 - Value of c is 31
Line 2 - Value of c is 11
Line 3 - Value of c is 210
Line 4 - Value of c is 2
Line 5 - Value of c is 1

比较运算符

下表显示了F#语言支持的所有比较运算符，这些二进制比较运算符可用于整数和浮点类型，这些运算符返回布尔类型的值。

假设变量A=10，变量B=20，则-

let mutable a : int32 = 21
let mutable b : int32 = 10

if (a = b) then
   printfn "Line 1 - a is equal to b"
else
   printfn "Line 1 - a is not equal to b"

if (a < b) then
   printfn "Line 2 - a is less than b"
else
   printfn "Line 2 - a is not less than b"

if (a > b) then
   printfn "Line 3 - a is greater than b"
else
   printfn "Line 3 - a is not greater than b"

(* Lets change value of a and b *)
a <- 5
b <- 20

if (a <= b) then
   printfn "Line 4 - a is either less than or equal to b"
else
   printfn "Line4 - a is a is greater than b"

编译并执行程序时，将产生以下输出-

Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than or equal to b

布尔运算符

下表显示了F#语言支持的所有布尔运算符。假设变量A= true ，变量B= false，然后-

let mutable a : bool = true;
let mutable b : bool = true;

if ( a && b ) then
   printfn "Line 1 - Condition is true"
else
   printfn "Line 1 - Condition is not true"

if ( a || b ) then
   printfn "Line 2 - Condition is true"
else
   printfn "Line 2 - Condition is not true"

(* lets change the value of a *)

a <- false
if ( a && b ) then
   printfn "Line 3 - Condition is true"
else
   printfn "Line 3 - Condition is not true"

if ( a || b ) then
   printfn "Line 4 - Condition is true"
else
   printfn "Line 4 - Condition is not true"

编译并执行程序时，将产生以下输出-

Line 1 - Condition is true
Line 2 - Condition is true
Line 3 - Condition is not true
Line 4 - Condition is true

按位运算符

按位运算符对位进行运算并执行逐位运算。&&&的真值表(按位AND)，|||(按位或)和^^^(按位异或)如下-

假设A=60;和B=13;现在以二进制格式，它们将如下所示-

A=0011 1100

B=0000 1101
-----------------
A&&&B=0000 1100

A ||| B=0011 1101

A ^^^ B=0011 0001

~~~ A=1100 0011

下表列出了F#语言支持的按位运算符。假设变量A=60，变量B=13，则-

let a : int32 = 60 // 60=0011 1100
let b : int32 = 13 // 13=0000 1101
let mutable c : int32 = 0

c <- a &&& b // 12=0000 1100
printfn "Line 1 - Value of c is %d" c

c <- a ||| b // 61=0011 1101
printfn "Line 2 - Value of c is %d" c

c <- a ^^^ b // 49=0011 0001
printfn "Line 3 - Value of c is %d" c

c <- ~~~a // -61=1100 0011
printfn "Line 4 - Value of c is %d" c

c <- a <<< 2 // 240=1111 0000
printfn "Line 5 - Value of c is %d" c

c <- a >>> 2 // 15=0000 1111
printfn "Line 6 - Value of c is %d" c

编译并执行程序时，将产生以下输出-

Line 1 - Value of c is 12
Line 2 - Value of c is 61
Line 3 - Value of c is 49
Line 4 - Value of c is 49
Line 5 - Value of c is 240
Line 6 - Value of c is 15

运算符优先

下表显示了F#语言中运算符和其他表达式关键字的优先顺序，从最低优先级到最高优先级。

let a : int32 = 20
let b : int32 = 10
let c : int32 = 15
let d : int32 = 5

let mutable e : int32 = 0
e <- (a + b) * c / d // ( 30 * 15 )/5
printfn "Value of (a + b) * c/d is : %d" e

e <- ((a + b) * c) / d // (30 * 15 )/5
printfn "Value of ((a + b) * c)/d is : %d" e

e <- (a + b) * (c / d) // (30) * (15/5)
printfn "Value of (a + b) * (c/d) is : %d" e

e <- a + (b * c) / d // 20 + (150/5)
printfn "Value of a + (b * c)/d is : %d" e

编译并执行程序时，将产生以下输出-

Value of (a + b) * c/d is : 90 
Value of ((a + b) * c)/d is : 90
Value of (a + b) * (c/d) is : 90 
Value of a + (b * c)/d is : 50