Perl 數值比較運算子示例

這些也被稱為關係運算符。假設變數 $a 持有 10，變數 $b 持有 20，那麼讓我們檢查以下數值比較運算子：

示例

嘗試以下示例以瞭解 Perl 中所有可用的數值比較運算子。將以下 Perl 程式複製並貼上到 test.pl 檔案中並執行該程式。

#!/usr/local/bin/perl
 
$a = 21;
$b = 10;

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

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

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

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

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

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

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

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

執行上述程式碼後，將產生以下結果：

Value of $a = 21 and value of $b = 10
$a == $b is not true
$a != $b is true
$a <=> $b returns 1
$a > $b is true
$a >= $b is true
$a < $b is not true
$a <= $b is not true