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📜  Julia 中的运算符

📅  最后修改于: 2021-11-25 04:49:25             🧑  作者: Mango

Julia 中的运算符是用于对变量和值执行运算的数学符号。这些符号用于进行算术和逻辑计算。运算符对其执行操作的变量称为Operands 。换句话说，我们可以说运算符操作操作数。
例如，考虑以下语句： 

c = a + b;

这里，“+”是被称为加法运算符和“a”和“b”是操作数运算符。加法运算符告诉编译器将操作数 ‘a’ 和 ‘b’ 相加。

运算符类型

Julia 中的运算符有六种类型：

  • 算术运算符
  • 按位运算符
  • 逻辑运算符
  • 赋值运算符
  • 向量化的“点”运算符
  • 关系运算符

算术运算符

算术运算运算符用于对操作数执行算术/数学运算。这些运算符包括加、减、乘、除等过程。例如： (+, -, *, /, %, +x, -x)。
算术运算运算符有两种类型：

  • 一元运算符：操作或使用单个操作数的运算符是一元运算运算符。例如：(+x, -x) 即一元加和一元减。
  • 二元运算符：操作或处理两个操作数的运算符是二元运算符。例如：(+, –, *, /)
Operator Description Syntax
+(unary plus) Unary plus: Identity operation +x
-(unary minus) Unary minus: Performs negation on operand -x
+ Binary plus: adds two operands x + y
– Binary minus: subtracts two operands x – y
* Multiplication(times): multiplies two operands x * y
/ Division (float): divides the first operand by the second and returns float value x / y
÷ Division (Integer): divides the first operand by the second and returns integer value x ÷ y
\ Division (Inverse): divides the second operand by the first(y/x) x \ y
^ Power: Raises x to the yth power x ^ y
% Modulus: returns the remainder when first operand is divided by the second x % y
! Negation: Changes bool value i.e. from true to false and vice versa x % y 
# Examples of Arithmetic Operator 
a = 9
b = 4
  
println("a = ", a)
println("b = ", b)
  
# Addition of numbers 
add = a + b 
println("Binary Addition: ", add) 
  
# Subtraction of numbers  
sub = a - b 
println("Binary Subtraction: ", sub) 
  
# Multiplication of number  
mul = a * b 
println("Binary Multiplication: ", mul) 
  
# Division(float) of number  
div1 = a / b 
println("Binary Division: ", div1) 
  
# Division(Integer) of number  
div2 = a ÷ b 
println("Integer Division: ", div2) 
  
# Division(floor) of number  
div3 = a \ b 
println("Inverse Division: ", div3) 
  
# Power of number 
pow = a ^ b 
println("Power Operation: ", pow) 
  
# Modulo of both number 
mod = a % b 
println("Modular Division: ", mod) 

输出：

a = 9
b = 4
Binary Addition: 13
Binary Subtraction: 5
Binary Multiplication: 36
Binary Division: 2.25
Integer Division: 2
Inverse Division: 0.4444444444444444
Power Operation: 6561
Modular Division: 1

按位运算符

按位运算符用于对数字的各个位进行操作。它们可以与任何整数类型一起使用。示例： (~, &, |, >>,

Operator Description Syntax
~ Bitwise NOT ~x
& Bitwise AND x & y
| Bitwise OR x | y
⊻ Bitwise XOR x ⊻ y
>>> Logical right shift x >>> y
>> Bitwise right shift x >> y
<< Bitwise/Logical left shift x << y 
# Examples of Bitwise operators
a = 48
b = 67
  
# Bitwise NOT operation 
println(~a)
  
# Bitwise AND operation  
println(a & b)
  
# Bitwise OR operation
println(a | b)
  
# Bitwise XOR operation 
println(a ? b)
  
# Logical right shift operation 
println(a >>> 2)
  
# Bitwise right shift operation 
println(a >> 2)
  
# Bitwise left shift operation 
println(a << 2)

输出： 

-49
0
115
115
12
12
192

逻辑运算符

逻辑运算符用于组合两个或多个条件/约束或补充考虑原始条件的评估。逻辑运算符是一个布尔值，真或假。例如，当考虑的两个条件都满足时，Julia 中表示为 ‘&&’运算符的逻辑 AND 返回 true。否则，它返回 false。因此，当 a 和 b 都为真（即非零）时， a && b 返回真。

Operator Description Syntax
&& Logical AND: True if both the operands are true x && y
|| Logical OR: True if either of the operands is true x || y
! Logical NOT: True if operand is false !x 
# Examples of Logical Operator
a = true
b = false
  
# Print if a and b both are False
println(a && b)
  
# Print if a or b is True
println(a || b)
  
# Print if not a is False
println(! a)

输出： 

false
true
false

赋值运算符

赋值运算符用于为变量赋值。赋值运算符左侧的操作数是可变的，并且所述赋值运算符右侧的操作数是一个值。右侧的值必须与左侧的变量具有相同的数据类型，否则编译器将引发错误。

Operator Description Syntax
= Assign value of right side of expression to left side operand x = y + z
+= Add AND: Add right side operand with left side operand and then assign to left operand a += b a = a + b
-= Subtract AND: Subtract right operand from left operand and then assign to left operand a -= b a = a – b
*= Multiply AND: Multiply right operand with left operand and then assign to left operand a *= b a = a * b
/= Divide AND: Divide left operand with right operand and then assign to left operand a /= b a = a / b
\= Inverse Divide AND: Divide right operand with left operand and then assign to left operand a \= b a = a \ b
÷= Integer Divide AND: Divide left operand with right operand and then assign to left operand a ÷= b a = a ÷ b
%= Modulus AND: Takes modulus using left and right operands and assign result to left operand a %= b a = a % b
^= Exponent AND: Calculate exponent(raise power) value using operands and assign value to left operand a ^= b a = a ^ b
&= Performs Bitwise AND on operands and assign value to left operand a &= b a = a & b
|= Performs Bitwise OR on operands and assign value to left operand a |= b a = a | b
⊻= Performs Bitwise xOR on operands and assign value to left operand a ⊻= b a = a ⊻ b
>>>= Performs Logical right shift on operands and assign value to left operand a>>>=b a=a>>>b >>= Performs Bitwise right shift on operands and assign value to left operand a >>= b a = a >> b
<<= Performs Bitwise left shift on operands and assign value to left operand a <<= b a = a << b 
# Examples of Assignment Operator 
a = 9
b = 4
  
println("a = ", a)
println("b = ", b)
  
# Addition of numbers 
a += b 
println("Binary Addition: ", a) 
  
# Subtraction of numbers  
a -= b 
println("Binary Subtraction: ", a) 
  
# Multiplication of number  
a *= b 
println("Binary Multiplication: ", a) 
  
# Division(float) of number  
a /= b 
println("Binary Division: ", a) 
  
# Division(Integer) of number  
a ÷= b 
println("Integer Division: ", a) 
  
# Division(floor) of number  
a \= b 
println("Inverse Division: ", a) 
  
# Power of number 
a ^= b 
println("Power Operation: ", a) 
  
# Modulo of both number 
a %= b 
println("Modular Division: ", a) 

输出

a = 9
b = 4
Binary Addition: 13
Binary Subtraction: 9
Binary Multiplication: 36
Binary Division: 9.0
Integer Division: 2.0
Inverse Division: 2.0
Power Operation: 16.0
Modular Division: 0.0

向量化的“点”运算符

“点”运算符(.) 用于执行二元运算，将其用于整个数组，逐个元素，一个接一个。例如，如果将幂 (^)运算符应用于 [4, 5, 6, 7] ^ 2 等数组，将导致错误，因为无法对数组执行“平方”。因此，“点”运算符开始使用。当与.^等二元运算一起使用时，它将对数组的每个元素执行运算。例如 – [4, 5, 6, 7] ^ 2 将导致 [4^2, 5^2, 6^2, 7^2]。
同样，此点运算符可以与其他二元运算符一起使用，例如 .=、.+、.- 等。

例子： 

# Julia program to illustrate
# use of 'dot' operator
  
# Creating array
A = [4, 5, 6, 7]
  
# Performing exponent binary operation
A = A ^ 2
  
# Performing exponent using 'dot' operation
A = A .^ 2 
println(A)

当在没有“点”运算符的情况下执行指数时，上面的代码将产生错误。这是因为不能对元素数组执行指数。
Julia-dot-operator

关系运算符

这些运算符用于检查诸如相等、大于、小于等关系。它们在比较后返回布尔结果，并广泛用于循环语句和条件 if-else 语句。

Operator Description Syntax
> Greater than: True if left operand is greater than the right x > y
< Less than: True if left operand is less than the right x < y
== Equal to: True if both operands are equal x == y
!=, ≠ Not equal to – True if operands are not equal x != y or x ≠ y
>=, ≥ Greater than or equal to: True if left operand is greater than or equal to the right x >= y or x ≥ y
<=, ≤ Less than or equal to: True if left operand is less than or equal to the right x <= y or x ≤ y

例子： 

# Examples of Relational Operators 
a = 13
b = 33
    
# a > b is False 
println(a > b) 
    
# a < b is True 
println(a < b) 
    
# a == b is False 
println(a == b) 
    
# a != b is True 
println(a != b) 
    
# a >= b is False 
println(a >= b) 
    
# a <= b is True 
println(a <= b) 

输出： 

false
true
false
true
false
true