运算符

-- Start

Perl 除了支持其他语言都支持的运算符外，它还支持一些特殊的运算符。

算术运算符

#!/usr/bin/perl

$x = 2;
$y = 3;

$r = $x + $y; #加
print "$rn";

$r = $x - $y; #减
print "$rn";

$r = $x * $y; #乘
print "$rn";

$r = $x / $y; #除
print "$rn";

$r = $x ** $y; #幂，相当于2的3次方
print "$rn";

$r = $x % $y; #余
print "$rn";

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数字比较运算符

#!/usr/bin/perl

$x = 2;
$y = 3;


if($x < $y) {
	print "$x < $yn";
}

if($x > $y) {
	print "$x > $yn";
}

if($x == $y) {
	print "$x == $yn";
}

if($x <= $y) {
	print "$x <= $yn";
}

if($x >= $y) {
	print "$x >= $yn";
}

if($x != $y) {
	print "$x > $yn";
}

$r = ($x <=> $y);
if($r == -1) {
	print "$x < $yn";
}
elsif ($r == 0) {
	print "$x == $yn";
}
elsif ($r == 1) {
	print "$x > $yn";
}

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串比较运算符

#!/usr/bin/perl

$x = 'a';
$y = 'b';


if($x lt $y) {
	print "$x less than $yn";
}

if($x gt $y) {
	print "$x greater than $yn";
}

if($x eq $y) {
	print "$x equals $yn";
}

if($x le $y) {
	print "$x less equal $yn";
}

if($x ge $y) {
	print "$x greater equal $yn";
}

if($x ne $y) {
	print "$x not equal $yn";
}

$r = ($x cmp $y);
if($r == -1) {
	print "$x less than $yn";
}
elsif ($r == 0) {
	print "$x equals $yn";
}
elsif ($r == 1) {
	print "$x greater than $yn";
}

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串连接和串重复

#!/usr/bin/perl

$x = 'a';
$y = 'b';

# 字符串连接
$r = $x.$y; # 结果为 ab
print "$rn";


# 字符串重复
$r = 'a' x 3; # 结果为 aaa

?

逻辑运算符

#!/usr/bin/perl

$x = 'a';
$y = 'b';
$z = 'c';


if($x > $y && $y > $z) {
	print "test &&n";
}

if($x > $y || $y > $z) {
	print "test ||n";
}

if(!($x > $y)) {
	print "test !n";
}


if($x > $y and $y > $z) {
	print "test andn";
}

if($x > $y or $y > $z) {
	print "test orn";
}

if(not($x > $y)) {
	print "test notn";
}

if($x > $y xor $y > $z) {
	print "test xorn";
}

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位运算符

#!/usr/bin/perl

# 按位与 &
# 按位或 |
# 按位非 ~
# 按位异或 ^
# 左移(相当于乘2) <<
# 右移(相当于除2) >>

赋值运算符

#!/usr/bin/perl

# =
# +=
# -=
# *=
# /=
# %=
# **=
# &=
# |=
# ^=
# .=

自增自减运算符

#!/usr/bin/perl

# ++
# --

逗号运算符

#!/usr/bin/perl

$a+=1,$b=$a;

$a+=1;
$b=$a;

条件运算符

#!/usr/bin/perl

$x = 2;
$y = 3;

$r = ($x > $y) ? ($x - $y) : ($y - $x);
print $r;

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-- 更多参见：Perl 精萃

-- 声 明：转载请注明出处 -- Last Updated on 2012-06-19 -- Written by ShangBo on 2012-06-18 -- End