Perl operators

Operator is a symbol that tells the compiler to perform a specific mathematical or logical operation, such as: 3+2=5.

The Perl language has a rich set of built-in operators. Let’s take a look at the commonly used ones:

Arithmetic operators
Comparison operators
Logical operators
Assignment operators
Bitwise operators
Quote operator
Other operators
Operator precedence

Arithmetic operators

In the table example, we set the variable $a to 10 and $b to 20.

##*Multiplication operation$a * $b The result is 200/ Division operation$b / $a The result is 2%Remainder operation, the remainder after integer division$b % $a The result is 0**Multiple to the power$a**$b The result is 10 20th power

Operator	Description	Instance
+	The result of addition operation	$a + $b is 30
-	The result of subtraction operation	$a - $b is -10

Example

#!/usr/bin/perl
 
$a = 10;
$b = 20;

print "$a = $a , $b = $b\n";

$c = $a + $b;
print '$a + $b = ' . $c . "\n";

$c = $a - $b;
print '$a - $b = ' . $c . "\n";

$c = $a * $b;
print '$a * $b = ' . $c . "\n";

$c = $a / $b;
print '$a / $b = ' . $c . "\n";

$c = $a % $b;
print '$a % $b = ' . $c. "\n";

$a = 2;
$b = 4;
$c = $a ** $b;
print '$a ** $b = ' . $c . "\n";

The above program execution output result is:

$a = 10 , $b = 20
$a + $b = 30
$a - $b = -10
$a * $b = 200
$a / $b = 0.5
$a % $b = 10
$a ** $b = 16

Comparison operator

In the table example, we set the variable $a to 10 and $b to 20.

OperatorDescriptionInstance==Check whether the values of the two operands are equal. If they are equal, the condition is true, otherwise it is false. ($a == $b) is false!=Check whether the values of the two operands are equal, if not equal The condition is true, otherwise it is false. ($a != $b) is true. <=>Check whether the values of the two operands are equal. If the number on the left is less than the number on the right, -1 is returned. If they are equal, 0 is returned. Returns 1 if the number on the left is greater than the number on the right. ($a <=> $b) returns -1. > Check whether the value of the left operand is greater than the value of the right operand. If so, the condition is true, otherwise it is false. ($a > $b) returns false. <Checks whether the value of the left operand is less than the value of the right operand. If so, the condition is true, otherwise it returns false. ($a < $b) returns true. >=Check whether the value of the left operand is greater than or equal to the value of the right operand. If so, the condition is true, otherwise it returns false. ($a >= $b) returns false. <=Checks whether the value of the left operand is less than or equal to the value of the right operand. If so, the condition is true, otherwise it returns false. . ($a <= $b) returns true.

Example

#!/usr/bin/perl
 
$a = 10;
$b = 20;

print "$a = $a , $b = $b\n";

if( $a == $b ){
   print "$a == $b 结果 true\n";
}else{
   print "$a == $b 结果 false\n";
}

if( $a != $b ){
   print "$a != $b 结果 true\n";
}else{
   print "$a != $b 结果 false\n";
}

$c = $a <=> $b;
print "$a <=> $b 返回 $c\n";

if( $a > $b ){
   print "$a > $b 结果 true\n";
}else{
   print "$a > $b 结果 false\n";
}

if( $a >= $b ){
   print "$a >= $b 结果 true\n";
}else{
   print "$a >= $b 结果 false\n";
}

if( $a < $b ){
   print "$a < $b 结果 true\n";
}else{
   print "$a < $b 结果 false\n";
}

if( $a <= $b ){
   print "$a <= $b 结果 true\n";
}else{
   print "$a <= $b 结果 false\n";
}

The execution output of the above program is:

$a = 10 , $b = 20
$a == $b 结果 false
$a != $b 结果 true
$a <=> $b 返回 -1
$a > $b 结果 false
$a >= $b 结果 false
$a < $b 结果 true
$a <= $b 结果 true

In the following table example, set the variable $a to "abc" and $b to "xyz", and then use the comparison operator to calculate the result.

Operator	Description	Instance
lt	Checks whether the string on the left is smaller than the string on the right, if so it returns true, otherwise it returns false.	($a lt $b) returns true.
gt	Check whether the string on the left is greater than the string on the right, if so, return true, otherwise return false.	($a gt $b) returns false.
le	Check whether the string on the left is less than or equal to the string on the right, if so, return true, otherwise return false.	($a le $b) Return true
ge	Check whether the string on the left is greater than or equal to the string on the right, if so Returns true, otherwise returns false.	($a ge $b) returns false.
eq	Check whether the string on the left is equal to the string on the right, if so, return true, otherwise return false.	($a eq $b) returns false.
ne	Check whether the string on the left is not equal to the string on the right, if so, return true, otherwise return false.	($a ne $b) Return true
cmp	If the string on the left is greater than the string on the right, return 1, if they are equal, return 0, or -1 if the string on the left is less than the string on the right.	($a cmp $b) returns -1.

Example

#!/usr/bin/perl
 
$a = "abc";
$b = "xyz";

print "$a = $a ，$b = $b\n";

if( $a lt $b ){
   print "$a lt $b 返回 true\n";
}else{
   print "$a lt $b 返回 false\n";
}

if( $a gt $b ){
   print "$a gt $b 返回 true\n";
}else{
   print "$a gt $b 返回 false\n";
}

if( $a le $b ){
   print "$a le $b 返回 true\n";
}else{
   print "$a le $b 返回 false\n";
}

if( $a ge $b ){
   print "$a ge $b 返回 true\n";
}else{
   print "$a ge $b 返回 false\n";
}

if( $a ne $b ){
   print "$a ne $b 返回 true\n";
}else{
   print "$a ne $b 返回 false\n";
}

$c = $a cmp $b;
print "$a cmp $b 返回 $c\n";

The execution output of the above program is:

$a = abc ，$b = xyz
abc lt $b 返回 true
$a gt $b 返回 false
$a le $b 返回 true
$a ge $b 返回 false
$a ne $b 返回 true
$a cmp $b 返回 -1

Assignment operator

In the table example, we set the variable $a to 10, $b is 20.

Operator	Description	Instance
=	Simple assignment operator, assigns the value of the right operand to the left operand	$c = $a + $b will assign the value of $a + $b to $c
+=	Addition and assignment operator, assigns the result of adding the right operand to the left operand to the left operand	$c += $a is equal to $ c = $c + $a
-=	Subtraction and assignment operator, assigns the result of subtracting the right operand from the left operand to the left operand	$c -= $a is equal to $c = $c - $a
#*=	Multiplication and assignment operator, multiplies the right operand Assign the result of the left operand to the left operand	$c = $a is equal to $c = $c $a
/=	Division and assignment operator, assigns the result of dividing the left operand by the right operand to the left operand	$c /= $a is equal to $c = $c / $a
%=	Modulo and assignment operator, find the modulus of two operands and assign it to the left operand	$c %= $a is equal to $c = $c % a
**=	The exponentiation and assignment operator finds the power of the two operands and assigns it to the left operand	$c = $a is equivalent to $c = $c $a

Example

#!/usr/bin/perl
 
$a = 10;
$b = 20;

print "$a = $a ，$b = $b\n";

$c = $a + $b;
print "赋值后 $c = $c\n";

$c += $a;
print "$c = $c ，运算语句 $c += $a\n";

$c -= $a;
print "$c = $c ，运算语句 $c -= $a\n";

$c *= $a;
print "$c = $c ，运算语句 $c *= $a\n";

$c /= $a;
print "$c = $c ，运算语句 $c /= $a\n";

$c %= $a;
print "$c = $c ，运算语句 $c %= $a\n";

$c = 2;
$a = 4;
print "$a = $a ， $c = $c\n";
$c **= $a;
print "$c = $c ，运算语句 $c **= $a\n";

The above program execution output result is:

$a = 10 ，$b = 20
赋值后 $c = 30
$c = 40 ，运算语句 $c += $a
$c = 30 ，运算语句 $c -= $a
$c = 300 ，运算语句 $c *= $a
$c = 30 ，运算语句 $c /= $a
$c = 0 ，运算语句 $c %= $a
$a = 4 ， $c = 2
$c = 16 ，运算语句 $c **= $a

Bit operations

Bit operators act on bits and perform operations bit by bit.

Set $a = 60, $b = 13, now expressed in binary format, they look like this:

$a = 0011 1100

$b = 0000 1101

-----------------

$a&$b = 0000 1100

$a|$b = 0011 1101

$a^$b = 0011 0001

~$a  = 1100 0011

The bitwise operators supported by Perl are shown in the following table:

Operator	Description	Instance
&	If both exist in The binary AND operator copies one of the two operands into the result.	($a & $b) will get 12, binary is 0000 1100
\|	If present in any operand, binary The OR operator copies one bit into the result.	($a \| $b) will get 61, which in binary is 0011 1101
^	if present in one of the operands but not Present in both operands simultaneously, the binary XOR operator copies one bit to the result.	($a ^ $b) will get 49, which in binary is 0011 0001
~	The two's complement operator is a unary operator, Has a "flipping" bit effect.	(~$a ) will give -61 , which is 1100 0011 in binary, 2's complement, signed binary number.
<<	Binary left shift operator. The value of the left operand is shifted left by the number of bits specified by the right operand.	$a << 2 will get 240 , which in binary is 1111 0000
>>	Binary right shift operator. The value of the left operand is shifted to the right by the number of bits specified by the right operand.	$a >> 2 will get 15, binary is 0000 1111

##Example

#!/usr/bin/perl
 
use integer;
 
$a = 60;
$b = 13;

print "$a = $a , $b = $b\n";

$c = $a & $b;
print "$a & $b = $c\n";

$c = $a | $b;
print "$a | $b = $c\n";

$c = $a ^ $b;
print "$a ^ $b = $c\n";

$c = ~$a;
print "~$a = $c\n";

$c = $a << 2;
print "$a << 2 = $c\n";

$c = $a >> 2;
print "$a >> 2 = $c\n";

The output result of the above program execution is ：

$a = 60 , $b = 13
$a & $b = 12
$a | $b = 61
$a ^ $b = 49
~$a = -61
$a << 2 = 240
$a >> 2 = 15

Logical operators

Perl logical operators are shown in the following table.

In the table example, we set the variable $a to true and $b to false.

OperatorDescriptionInstanceand Logical AND operator. If both operands are true, the condition is true. ($a and $b) is false. &&C-style logical AND operator. The condition true($a && $b) is false if both operands are true. orLogical OR operator. The condition is true if either of the two operands is non-zero. ($a or $b) is true. ||C-style logical OR operator. The condition is true if either of the two operands is non-zero. ($a || $b) is true. notLogical NOT operator. Used to invert the logical state of the operand. If the condition is true, the logical NOT operator will make it false. not($a and $b) is true.

Example

#!/usr/bin/perl
 
$a = true;
$b = false;

print "$a = $a , $b = $b\n";

$c = ($a and $b);
print "$a and $b = $c\n";

$c = ($a  && $b);
print "$a && $b = $c\n";

$c = ($a or $b);
print "$a or $b = $c\n";

$c = ($a || $b);
print "$a || $b = $c\n";

$a = 0;
$c = not($a);
print "not($a)= $c\n";

The above program execution output result is:

$a = true , $b = false
$a and $b = false
$a && $b = false
$a or $b = true
$a || $b = true
not($a)= 1

Quotation mark operation

Perl quotation mark operator is shown in the following table.

Operator	Description	Instance
q{ }	Add single quotes to the string	q{abcd} The result is 'abcd'
qq{ }	Add double quotes to the string	qq{abcd} The result is "abcd"
qx{ }	Add backticks to the string	qx{ abcd} The result is `abcd`

Example

#!/usr/bin/perl
 
$a = 10;
 
$b = q{a = $a};
print "q{a = $a} = $b\n";

$b = qq{a = $a};
print "qq{a = $a} = $b\n";

# 使用 unix 的 date 命令执行
$t = qx{date};
print "qx{date} = $t\n";

The above program execution output result is:

q{a = $a} = a = $a
qq{a = $a} = a = 10
qx{date} = 2016年 6月10日 星期五 16时22分33秒 CST

Other operators

In addition to the operators we mentioned above, Perl also supports the following operators:

Operator	Description	Example
.	The period (.) is used to connect two strings.	If $a="run", $b="oob", the result of $a.$b is "php"
x	x The operator returns the number of times a string is repeated.	('-' x 3) The output is ---.
..	.. is the range operator.	(2..5) The output result is (2, 3, 4, 5)
++	Increment operator, integer The value increases by 1	$a =10, $a++ will output 11
--	Decrement operator, the integer value decreases by 1	$a =10, $a-- The output is 9
->	Arrows are used to specify methods of a class	$obj->$a represents the $a method of object $obj.

Example

#!/usr/bin/perl
 
$a = "run";
$b = "oob";

print "$a  = $a ， $b = $b\n";
 
$c = $a . $b;
print "$a . $b = $c\n";

$c = "-" x 3;
print "\"-\" x 3 = $c\n";

@c = (2..5);
print "(2..5) = @c\n";

$a = 10;
$b = 15;
print "$a  = $a ， $b = $b\n";

$a++;
$c = $a ;
print "$a 执行 $a++ = $c\n";

$b--;
$c = $b ;
print "$b 执行 $b-- = $c\n";

The execution output of the above program is:

$a  = run ， $b = oob
$a . $b = php
"-" x 3 = ---
(2..5) = 2 3 4 5
$a  = 10 ， $b = 15
$a 执行 $a++ = 11
$b 执行 $b-- = 14

Operator priority

The following table lists the operator priority of Perl language ：

##-, ~, !From right to left**From right To left##=~, !~*, /, %, x+, -, .<< , >>-e, -r,<, <=, >, >=, lt, le, gt, ge==, != , <=>, eq, ne, cmp&|, ^&||..? and :=, +=, -=, *=,Others,notandor, xorExample

Operator	Associativity
++, --	None


From left to right
From left to right
From left to right
From left to right
None
from left to right
from left to right
from left to right
From left to right
From left to right
From left to right
From left to right
Right to left
Right to left

From left to right
Left to right
Left to right
From left to right

#!/usr/bin/perl
 
$a = 20;
$b = 10;
$c = 15;
$d = 5;
$e;

print "$a  = $a, $b = $b, $c = $c ，$d = $d\n";
 
$e = ($a + $b) * $c / $d;
print "($a + $b) * $c / $d  = $e\n";

$e = (($a + $b) * $c )/ $d;
print "(($a + $b) * $c) / $d  = $e\n";

$e = ($a + $b) * ($c / $d);
print "($a + $b) * ($c / $d )  = $e\n";

$e = $a + ($b * $c ) / $d;
print "$a + ($b * $c )/ $d  = $e\n";

The output result of the execution of the above program is:

$a  = 20, $b = 10, $c = 15 ，$d = 5
($a + $b) * $c / $d  = 90
(($a + $b) * $c) / $d  = 90
($a + $b) * ($c / $d )  = 90
$a + ($b * $c )/ $d  = 50

← Perl loop

Perl date and time →

Perl operators

Arithmetic operators

Example

Example

Assignment operator

Example

Bit operations

#!/usr/bin/perl use integer; $a = 60; $b = 13; print "$a = $a , $b = $b\n"; $c = $a & $b; print "$a & $b = $c\n"; $c = $a | $b; print "$a | $b = $c\n"; $c = $a ^ $b; print "$a ^ $b = $c\n"; $c = ~$a; print "~$a = $c\n"; $c = $a << 2; print "$a << 2 = $c\n"; $c = $a >> 2; print "$a >> 2 = $c\n";

Example

Quotation mark operation

Example

Other operators

Example

Operator priority

The output result of the execution of the above program is:

php.cn