Perl 字串等值運算子示例

下面是等值運算子列表。假設變數 $a 儲存 "abc"，變數 $b 儲存 "xyz"，那麼讓我們檢查以下字串等值運算子：

示例

嘗試以下示例以瞭解 Perl 中所有可用的字串等值運算子。將以下 Perl 程式複製並貼上到 test.pl 檔案中並執行此程式。

#!/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";

執行上述程式碼後，將產生以下結果：

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