Perl 字符串等值运算符示例

下面是等值运算符列表。假设变量 $a 存储 "abc"，变量 $b 存储 "xyz"，那么让我们检查以下字符串等值运算符：

示例

尝试以下示例以了解 Perl 中所有可用的字符串等值运算符。将以下 Perl 程序复制并粘贴到 test.pl 文件中并执行此程序。

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

print "Value of \$a = $a and value of \$b = $b\n";

if( $a lt $b ) {
   print "$a lt \$b is true\n";
} else {
   print "\$a lt \$b is not true\n";
}

if( $a gt $b ) {
   print "\$a gt \$b is true\n";
} else {
   print "\$a gt \$b is not true\n";
}

if( $a le $b ) {
   print "\$a le \$b is true\n";
} else {
   print "\$a le \$b is not true\n";
}

if( $a ge $b ) {
   print "\$a ge \$b is true\n";
} else {
   print "\$a ge \$b is not true\n";
}

if( $a ne $b ) {
   print "\$a ne \$b is true\n";
} else {
   print "\$a ne \$b is not true\n";
}

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

执行上述代码后，将产生以下结果：

Value of $a = abc and value of $b = xyz
abc lt $b is true
$a gt $b is not true
$a le $b is true
$a ge $b is not true
$a ne $b is true
$a cmp $b returns -1