📜  Perl-运营商

📅  最后修改于: 2020-10-16 05:28:51             🧑  作者: Mango


什么是运算符?

使用表达式4 + 5等于9可以给出简单答案。这里的4和5称为操作数,而+称为运算符。 Perl语言支持许多运算符类型,但以下是重要且最常用的运算符列表-

  • 算术运算符
  • 平等经营者
  • 逻辑运算符
  • 赋值运算符
  • 按位运算符
  • 逻辑运算符
  • 类引用运算符
  • 杂项运算符

让我们一一看一下所有的运算符。

Perl算术运算符

假设变量$ a持有10而变量$ b持有20,那么以下是Perl算术运算符-

显示范例

Sr.No. Operator & Description
1

+ ( Addition )

Adds values on either side of the operator

Example − $a + $b will give 30

2

– (Subtraction)

Subtracts right hand operand from left hand operand

Example − $a – $b will give -10

3

* (Multiplication)

Multiplies values on either side of the operator

Example − $a * $b will give 200

4

/ (Division)

Divides left hand operand by right hand operand

Example − $b / $a will give 2

5

% (Modulus)

Divides left hand operand by right hand operand and returns remainder

Example − $b % $a will give 0

6

** (Exponent)

Performs exponential (power) calculation on operators

Example − $a**$b will give 10 to the power 20

Perl平等运算符

这些也称为关系运算符。假设变量$ a持有10,变量$ b持有20,那么让我们检查以下数值相等运算符-

显示范例

Sr.No. Operator & Description
1

== (equal to)

Checks if the value of two operands are equal or not, if yes then condition becomes true.

Example − ($a == $b) is not true.

2

!= (not equal to)

Checks if the value of two operands are equal or not, if values are not equal then condition becomes true.

Example − ($a != $b) is true.

3

<=>

Checks if the value of two operands are equal or not, and returns -1, 0, or 1 depending on whether the left argument is numerically less than, equal to, or greater than the right argument.

Example − ($a <=> $b) returns -1.

4

> (greater than)

Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.

Example − ($a > $b) is not true.

5

< (less than)

Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.

Example − ($a < $b) is true.

6

>= (greater than or equal to)

Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.

Example − ($a >= $b) is not true.

7

<= (less than or equal to)

Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.

Example − ($a <= $b) is true.

以下是股权运算符列表。假设变量$ a持有“ abc”,变量$ b持有“ xyz”,那么,让我们检查以下字符串相等运算符-

显示范例

Sr.No. Operator & Description
1

lt

Returns true if the left argument is stringwise less than the right argument.

Example − ($a lt $b) is true.

2

gt

Returns true if the left argument is stringwise greater than the right argument.

Example − ($a gt $b) is false.

3

le

Returns true if the left argument is stringwise less than or equal to the right argument.

Example − ($a le $b) is true.

4

ge

Returns true if the left argument is stringwise greater than or equal to the right argument.

Example − ($a ge $b) is false.

5

eq

Returns true if the left argument is stringwise equal to the right argument.

Example − ($a eq $b) is false.

6

ne

Returns true if the left argument is stringwise not equal to the right argument.

Example − ($a ne $b) is true.

7

cmp

Returns -1, 0, or 1 depending on whether the left argument is stringwise less than, equal to, or greater than the right argument.

Example − ($a cmp $b) is -1.

Perl赋值运算符

假设变量$ a持有10,变量$ b持有20,那么下面是Perl中可用的赋值运算符及其用法-

显示范例

Sr.No. Operator & Description
1

=

Simple assignment operator, Assigns values from right side operands to left side operand

Example − $c = $a + $b will assigned value of $a + $b into $c

2

+=

Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand

Example − $c += $a is equivalent to $c = $c + $a

3

-=

Subtract AND assignment operator, It subtracts right operand from the left operand and assign the result to left operand

Example − $c -= $a is equivalent to $c = $c – $a

4

*=

Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand

Example − $c *= $a is equivalent to $c = $c * $a

5

/=

Divide AND assignment operator, It divides left operand with the right operand and assign the result to left operand

Example − $c /= $a is equivalent to $c = $c / $a

6

%=

Modulus AND assignment operator, It takes modulus using two operands and assign the result to left operand

Example − $c %= $a is equivalent to $c = $c % a

7

**=

Exponent AND assignment operator, Performs exponential (power) calculation on operators and assign value to the left operand

Example − $c **= $a is equivalent to $c = $c ** $a

Perl按位运算符

按位运算符对位进行运算并逐位执行操作。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

Perl语言支持以下Bitwise运算符,假设$ a = 60;和$ b = 13

显示范例

Sr.No. Operator & Description
1

&

Binary AND Operator copies a bit to the result if it exists in both operands.

Example − ($a & $b) will give 12 which is 0000 1100

2

|

Binary OR Operator copies a bit if it exists in eather operand.

Example − ($a | $b) will give 61 which is 0011 1101

3

^

Binary XOR Operator copies the bit if it is set in one operand but not both.

Example − ($a ^ $b) will give 49 which is 0011 0001

4

~

Binary Ones Complement Operator is unary and has the efect of ‘flipping’ bits.

Example − (~$a ) will give -61 which is 1100 0011 in 2’s complement form due to a signed binary number.

5

<<

Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.

Example − $a << 2 will give 240 which is 1111 0000

6

>>

Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.

Example − $a >> 2 will give 15 which is 0000 1111

Perl逻辑运算符

Perl语言支持以下逻辑运算符。假设变量$ a成立,变量$ b成立,然后-

显示范例

Sr.No. Operator & Description
1

and

Called Logical AND operator. If both the operands are true then then condition becomes true.

Example − ($a and $b) is false.

2

&&

C-style Logical AND operator copies a bit to the result if it exists in both operands.

Example − ($a && $b) is false.

3

or

Called Logical OR Operator. If any of the two operands are non zero then then condition becomes true.

Example − ($a or $b) is true.

4

||

C-style Logical OR operator copies a bit if it exists in eather operand.

Example − ($a || $b) is true.

5

not

Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.

Example − not($a and $b) is true.

类引用运算符

Perl语言支持以下类似Quote的运算符。在下表中,{}代表您选择的任何一对定界符。

显示范例

Sr.No. Operator & Description
1

q{ }

Encloses a string with-in single quotes

Example − q{abcd} gives ‘abcd’

2

qq{ }

Encloses a string with-in double quotes

Example − qq{abcd} gives “abcd”

3

qx{ }

Encloses a string with-in invert quotes

Example − qx{abcd} gives `abcd`

杂项运算符

Perl语言支持以下杂类运算符。假设变量a持有10而变量b持有20然后-

显示范例

Sr.No. Operator & Description
1

.

Binary operator dot (.) concatenates two strings.

Example − If $a = “abc”, $b = “def” then $a.$b will give “abcdef”

2

x

The repetition operator x returns a string consisting of the left operand repeated the number of times specified by the right operand.

Example − (‘-‘ x 3) will give —.

3

..

The range operator .. returns a list of values counting (up by ones) from the left value to the right value

Example − (2..5) will give (2, 3, 4, 5)

4

++

Auto Increment operator increases integer value by one

Example − $a++ will give 11

5

Auto Decrement operator decreases integer value by one

Example − $a– will give 9

6

->

The arrow operator is mostly used in dereferencing a method or variable from an object or a class name

Example − $obj->$a is an example to access variable $a from object $obj.

Perl运算符优先级

下表列出了从最高优先级到最低优先级的所有运算符。

显示范例

left    terms and list operators (leftward)
left    ->
nonassoc    ++ --
right    **
right    ! ~ \ and unary + and -
left    =~ !~
left    * / % x
left    + - .
left    << >>
nonassoc    named unary operators
nonassoc    < > <= >= lt gt le ge
nonassoc    == != <=> eq ne cmp ~~
left    &
left    | ^
left    &&
left    || //
nonassoc    ..  ...
right    ?:
right    = += -= *= etc.
left    , =>
nonassoc    list operators (rightward)
right    not
left    and
left    or xor